本書意欲探討中晚唐時，中央政府與地方政府之間的財政關係，並分析兩者之間的互動變化，如何改變晚唐時州與藩鎮的財政力量，並最終導致地方獨立權力的上升，而且是否埋下五代北宋道一集財政機構出現的契機。筆者選擇兩稅法中的稅收分配模式──兩稅三分，和非專賣性質的稅茶作為觀察切入點。
兩稅法是德宗建中元年（780）由宰相楊炎推動，旨在改善自安史之亂後，中央政府稅收不足、地方政府擅自課徵雜稅的狀況，並且為了適應人口大規模流動：取消人頭稅，改為單一稅種──資產稅，下令地方政府停止各項雜稅的徵收。既然改為兩稅法，自然也需重新安排稅收於各層級的分配，依循中唐以前分配模式稍做改良，加入藩鎮這個新的行政單位，形成兩稅三分──留州、留使、上供的模式。因兩稅法以現錢計稅和量出為入的兩大原則，兩稅法中預留給各個行政層級的財政預算並不會有太多餘羨，對藩鎮和州而言，留州與留使錢物無法應付突發狀況；而且兩稅法實施後，中央政府對地方財政的態度是，地方政府需自理預算的剩餘或虧損。基於這些因素，中央政府與地方政府之間對兩稅法的態度，是合作多於對抗。
稅茶設置的時間晚於兩稅法，於德宗貞元九年（793）開始徵收。最初規劃兩種徵收模式，一種為於市場內向販茶的商人課徵，一種是於茶山、茶園附近向購茶的茶商課徵。特別的是，稅茶雖由鹽鐵轉運使建議開徵，但中央政府最終基於權力平衡的考量，將稅茶管理權交給成立未久的戶部司。但戶部司的行政資源，無法同時顧及兩種截然不同的稅收模式，以及日益嚴重的茶葉走私交易活動也困擾著中央政府。於是穆宗長慶元年時，鹽鐵轉運使王播推動稅茶分區管理，將兩種稅收方式改成剩下產地徵收，並且以產地作為劃分，江淮、嶺南、兩浙、福建等生產地區的稅茶，改鹽鐵轉運司負責辦理，戶部司僅剩劍南地區的稅茶業務。雖改為類似榷鹽的運作方式，但對遏止走私活動的助益不大，故文宗大和九年九月起，鹽鐵轉運使王涯推動茶葉專賣政策，內容甚為激進，要求江淮等地區的茶戶遷徙至國有茶園中，並焚燬茶葉庫存。稅茶改榷茶，因遭遇激烈反彈與甘露之變，同年底旋即取消國有茶園政策但仍維持榷茶，並於隔年──開成元年由鹽鐵轉運使李石宣布茶稅「復貞元之制」，即改榷茶為稅茶。
李石除恢復稅茶外，也同步將稅茶的徵收權下放至州，並由藩鎮監管。這項政策的制訂，與前年底王涯激烈的茶園國有政策一樣，皆是要應付當時盛行的茶葉走私交易活動，也凸顯出鹽鐵轉運使發展至唐末時，已經沒有足夠的行政資源，一面直接管理商業稅、專賣稅，一面又緝捕走私商人、團伙，加上地方政府兩稅收入不足，也私自設關卡向商人課徵雜稅，於是鹽鐵轉運司下放稅茶徵收權，與地方政府共享稅茶的稅收，並把查緝走私交易的工作也交由地方政府處置。中央政府雖採取多項措施制止茶葉走私交易活動，但始終無法根絕走私交易；開成元年後，前後多次加重走私茶商、團伙的罰責，並加強地方政府的查緝力道，直到宣宗大中中葉，鹽鐵轉運使裴休提出「稅茶十二條」，對稅茶的管理作出通盤檢討，方初見成效。
從兩稅三分至稅茶的走私交易活動猖獗，呈現出中央政府對直接管理稅收的困難，以及地方政府的難為之處。兩稅三分的留州、留使錢物，在量出制入的原則下，已很難有餘羨應付突發性狀況，還需從有限經費中設法籌出藩帥以「羨餘」名義上貢皇帝的錢財。這樣的情況下，地方政府自然往其他方向課徵雜稅，當時日漸繁盛的商業交易提供一個稅收管道，於是中央政府與地方政府紛紛將注意力放到這些商品上，榷酒、鹽榷、稅茶都是這時期出現，地方政府除在交通要道設置邸店私自課徵外，甚至參與投資茶葉走私交易，換言之，地方政府在茶葉交易中扮演三個角色：徵稅管理者、查緝走私者以及參與走私者。這樣混亂的局面，讓更多合法茶商選擇成為走私茶商，使得直到裴休對整套管理機制進行全盤檢討後，走私活動才有減緩的跡象。除有地方政府經費不足的現象外，晚唐時，以直接管理而得到極高收益的鹽鐵轉運司，已無法負荷直接在地方管理稅目的高負擔，另外二司──度支司與戶部司則在更早時，就將多數稅目轉交地方政府徵收、管理。這間接影響日後五代時，三個獨立的財政使職，合併為單個財政使職：三司使的發展。而鹽鐵轉運使於晚唐時逐步放棄對稅茶和鹽榷的管理，一一將權力下放至地方政府，也標誌著另立一套可直接課稅的財政系統嘗試失敗，使得三司使的地方機構，邁向北宋路級轉運使的轉型。

This doctoral dissertation intends to explore the financial relationship between the central government and local governments in the middle and late Tang dynasties, and analyze how the interaction between the two changed the financial power of prefectures (Zhou 州) and Fanzhen (feudal towns 藩鎮) in the late Tang Dynasty, Ultimately led to the rise of local independent, and whether it planted the opportunity for the emergence of a set of financial institutions in the Five Dynasties Northern Song Dynasty. I chooses the tax distribution model in the Two Tax Laws (兩稅法) , and tea tax (稅茶) as the starting point for observation.
The Two Tax Law was established by Prime Minister Yang Yan (楊炎) in first year of Jianzhong (建中元年), aiming to improve the situation of insufficient tax collection by the central government and unauthorized collection of miscellaneous taxes by local governments since the Anshi Rebellion (安史之亂), and in order to adapt to the large-scale movement of the population: the poll tax was abolished and replaced with a single tax, the asset tax, and the local government was ordered to stop the collection of various miscellaneous taxes. In response to the accession of the clan towns, the tax distribution model was also divide the Two Tax Law into three parts: Shanggong (上供), Liushi (留使), Liuzhou (留州). For the towns and prefectures, staying in the prefecture and keeping money and goods cannot cope with emergencies; Moreover, after the implementation of the Two Tax laws, the attitude of the central government towards local finances is that local governments need to take care of the surplus or loss of their own budgets. Based on these factors, the attitude between the central government and local governments towards the Two Tax Law is more cooperative than confrontational.
The tax tea was set up in the ninth year of the Zhenyuan. (貞元) Initially, two levy models were planned, one was levied on tea merchants selling tea in the market, and the other was levied on tea merchants who bought tea near tea gardens. Although the tax tea was proposed by the Yantiezhuanyunshi (鹽鐵轉運使), the central government finally handed over the management of tax tea to the newly established the Hubushi (戶部使) based on the consideration of the balance of power. But the Hubushi lack of administrative resources to accommodate two very different tax models, as well as the growing tea smuggling trade, also plagued the central government. Therefore, in the first year of Changqing (長慶), Wangbao (王播) promote the management of tax tea zoning, changing the two tax methods to the remaining production area collection, and taking the origin as the division, the tax tea in Jianghuai (江淮), Lingnan (嶺南), Liangzhe (兩浙), Fujian (福建)under the Yantiezhuanyunshi control, and the Hubushi only the tax tea business in the Jiannan (劍南) area remains. in September of Dahe’s (大和) ninth year, WangYa (王涯) promoted a tea monopoly policy, which was very radical, requiring tea farmers in Jianghuai and other regions to migrate to state-owned tea gardens and burn their own tea stocks. Due to the fierce backlash and Sweet Dew incident (甘露之變), the state-owned tea garden policy was immediately cancelled at the end of the same year, and LiShi (李石) changed tea to tax tea in the first year of Kaicheng (開成).
In addition to restoring tax tea, LiShi also delegated the collection of tax tea to the prefecture and placed it under the supervision of the fanzhen. This policy was formulated to deal with the prevalent tea smuggling trade, and highlighted that the Yantiezhuanyunshi had no more administrative resources in late Tang dynasty. Therefore, the Yantiezhuanyunshi department delegated the right to collect tax tea, shared the tax revenue of tax tea with local governments, and handed over the work of investigating smuggling transactions to local governments. After the first year of Kaicheng, the punishment of tea smugglers and gangs was repeatedly increased, and the investigation and seizure of local governments was strengthened, until the middle year of the Dazhong (大中), PeiXiu (裴休) proposed twelve articles on tax tea, and made a comprehensive review of the management of tax tea, and the initial results were achieved.
The rampant tea smuggling trade shows the difficulties faced by the central government in directly managing tax revenues, as well as the difficulties of local governments. In this case, local governments naturally imposed miscellaneous taxes, and the flourishing commercial transactions at that time provided a tax channel, so the central and local governments focused their attention on these goods. In summary, local governments play three roles in the tea trade: tax collectors, arrest smugglers, and participate in smugglers. This indirectly affected the development of three separate financial envoys over the next five generations, merged into a single treasury: the three envoys. The Yantiezhuanyunshi made the gradual abandonment of the management of tax tea and salt in the late Tang Dynasty, and delegated power to the local government one by one, which also marked the failure of the attempt to establish a separate financial system that could be directly taxed, so that the local institutions of the three envoys moved towards the transformation of the Northern Song Dynasty's lu-level (路) transfer envoys.