Abstract: Although some scholars have regarded the proto-province in the early period of the Tang Dynasty as the predecessor of the pre-province in the Jin and Yuan Dynasty,but in fact it had been maintained no more than ten years,and can not be understood as a level of local setup.This paper starts with the background of establishment of the proto-provinces,and goes further into the analysis of the reasons for its being abolished and not transformed into a fixed organization.The reasons are as follows: first of all,the administrators of the proto-provinces held the massive power.A unified management of the military affairs and the administrative affairs causes the local military officers to become self-important,to be liable to make rebellion,therefore their removal is also inevitable;Secondly,the purposes to set up the six proto-provinces are different.In normal ruling order,the position and function of the organs at the same level should be almost no different,but among the six proto-provinces,although the proto-provinces like Shanndong were established for purpose of exercising administrative function,some proto-provinces as Xianzhou,Dongnan and Shandong,are set up for other purposes.