Connecting the regional power grid through HVDC makes the DC interconnected asynchronous power grid appear in the system, which weakens the mutual support ability between the regional power grids. In this paper, aiming at the frequency adjustment problem after the power disturbance occurs in the regional power grid, the cooperative power allocation method of HVDC and AGC is proposed. Firstly, the frequency adjustment model of power system and the control strategy of HVDC participating in primary frequency regulation are introduced. Secondly, based on the multi-agent consistency theory, the method of cooperative power distribution between HVDC and AGC is designed. In the secondary frequency regulation stage, the adjustment cost of each unit and HVDC is considered, and the power distribution algorithm is designed with the adjustment cost as the consistency state variable to realize the cooperative control between HVDC and AGC, through the power adjustment of HVDC, the connected asynchronous power grid can also bear part of the power imbalance according to the adjustment cost and reduce the overall adjustment cost of the interconnected system. The effectiveness of the proposed method is verified by an example..