The invention provides an AVC adjustment sensitivity calculating method based on EMS historical data. The AVC adjustment sensitivity calculating method can overcome the problem that normal use of an AVC function is affected due to deviation between an AVC adjustment sensitivity parameter of a system and the reality, since the AVC adjustment sensitivity parameter is not verified for a long time, such that the system maintenance personnel cannot perceive the adjustment sensitivity change caused by changes of a power grid operating mode or a field operating environment during operation of the AVCsystem at present. According to the AVC adjustment sensitivity calculating method, the statistically significant AVC adjustment sensitivity data can be used for verifying and correcting the AVC adjustment sensitivity parameter in the existing system, thereby realizing more precise control of voltage reactive power of the AVC system.