The state estimation data of the grid in mountainous area couldn't been used by the real-time control frequently. The existing AVC regional optimization control method rely on state estimation data, and cannot be implemented normally in the mountainous area. This paper proposed a novel regional optimal control method of reactive power & voltage for the grid in mountainous area based on AVC. It does not rely on state estimation data. According to the AVC control target priority of the mountainous area grid, the corresponding optimal control strategy is presented. And a novel accurate selection method of 10kV bus voltage control target value is proposed. The application data in typical mountainous area grid show that the proposed method significantly improved the voltage qualification rate without state estimation.