The invention provides to a prefecture-county integrated automatic voltage control method. The control method comprises the following steps of: obtaining a power grid model, a control model and real-time data required for automatic voltage control; carrying out prefecture and county regional voltage idle work optimization calculation and constructing a control strategy system to obtain the controlling quantity of prefecture and county plant stations; distributing the obtained controlling quantity to a prefecture and county plant stations to be executed in a centralized manner through the prepositive communication of a scheduling automatic system; carrying out regional monitoring and regional management examining statistics; and returning for circulation so as to carry out periodic control monitoring and statistics when the voltage control period is reached. A prefecture-county shared automatic voltage control system more reasonably effectively utilizes various idle work adjustment and voltage control measures in a power grid, the construction investment of the system is reduced, and the system maintenance management is flexible and convenient.