The disadvantage of Beijing-Tianjin-Tangshan power grid operation control mode is that the control effect is poorer and the spare capacity demand is big, this paper puts forward a new coordinated control strategy. First of all, this paper describes the relationship between the load, frequency, the output of generating unit, the tie line power and the area control error relationship of the whole power grid, according to the regional automatic generation control performance assessment criteria, concludes the characteristics of regional unit adjustment. This paper analyzes the contradiction between them, and then proposes a coordinated control strategy between the Beijing-Tangshan power grid and Tianjin power grid. The case simulation results prove the superiority and feasibility of the new coordinated control strategy. Compared with the original, the new strategy reduces the volatility of the unit, shortens the recovery time of frequency, and has a certain practical significance.