Abstract: Supervision was efficient in the earlier stageof the Tang Dynasty, which ensured the control of the central feudal government over the local ones. However, the supervisory system was damaged in middle and later stages the officials assigned to making inspection tours to local places evolved into resident officials and further became chief local officials, who took over both administrative and supervisory powers, and enjoined infringement on and seized the supervisory power from the supervisory organ. The root cause was the fact that the independent organization franework and the mechanism of independent exercise of power by the supervisory organ had been damaged.

Key words: Tang Dynasty, Local Supervisory Powr, Weakening, organizational system