唐朝自立國以來便持續推行斷屠政策，目前的研究多將此一政策解讀為宗教性的行為，但政策的制定必然有其複雜的考量，以因應龐大帝國的運作，並且適應各時各地的現實需求。每一道斷屠政策隨著時空的不同，其背後是否有不同的動機？為解答此問題，本文收集唐朝政府頒布的五十餘道斷屠政策，依照頒布的時間排列，觀察斷屠政策的整體演變。透過本文的討論可以發現，宗教因素與皇帝誕辰忌日固然為政策制定的原因之一，但斷屠政策同時也反映唐代不同時期牲畜供需失衡的問題：國初是為了重建，保護具有勞動力的牲畜；盛世則是飲食習慣的改變與對外戰爭的消耗，導致需求大過於供給；安史之亂後，中央政府失去西北畜牧區，對內控制力亦削弱，為了維持耕牛數量再度採取國初保護生產力的政策。

At the beginning of its establishment, the Tang government continued the prohibitions on livestock slaughter. Current research often attribute a religious basis to these prohibitions. If the whole country was pious at the time, why were the policies frequently promulgated and why did they include such a large number of situations? Were there other, non-religious motivations driving these prohibitions? I arrange all the policies in chronological order and observe the relation between the prohibitions and social transformation. It certainly is the case that the prohibitions of livestock slaughter were based on religion and the commemoration of emperors' dates of birth, but they also reflected the need in Tang society to maintain the livestock population. In the beginning, the government protected livestock in order to rebuild. Later, in the golden age of the Tang, we see another shift in the motivations behind these policies, particularly through the changes in dietary habits and the demands of war. In the aftermath of the An-Lushan rebellion, they lost their livestock area in the northwest. In addition, the government was losing control over many regions of its empire. Thus we can see that religion is not the only factor driving these policies. Over the course of the Tang Dynasty, regardless of the challenges they were facing, maintaining the livestock population was also a primary consideration.