The present paper attempts to reinterpret the organization and administration of the tianguan 田官 institutions situated in Hexi 河西, which were established by the Han government during the reign of Emperor Wu as one of the regional administrations duguan 都官, and served as important units in military farming 軍屯. The paper argues that nongzhang 農長, instead of being merely a district 鄉 level official subordinate to nongling 農令, should be classified as the magistrate in the bureaucracy of tianguan; and nongsefu 農嗇夫 should be considered as the real district-level official of tianguan. The paper further examines the changes within the bureaucratic framework of tianguan in Juyan 居延, showing that there were two radical reformations in its framework: the first one occurred between the reign of Emperor Zhao and Emperor Xuan, which led to the establishment of a more organized structure and uniform boundary; the second happened in Wang Mang’s reign as part of his land reforms, which involved not only a renaming of the bureau from tianguan to xiantian 閒田, but also a restructuring from a bureau which was not committed to civilian administration, to a quasi-county organization that proc﹣essed direct control over people within its jurisdiction. The remaining parts of the paper primarily use xingma 騂馬 tianguan in Jianshui 肩水 as an example, demonstrating the communications between tianguan and regional military units, i.e. commandants 都尉 and companies 候官, where the tianguan was located, and revealing that although tianguan was theoretically a regional branch office directly controlled by the Superintendent of Agriculture 大司農, it was supervised by regional military units in most administrative aspects.