With the large-scale high-voltage direct current(HVDC) infeed, the safety, stability and economic operation of the receiving-end power grid is facing greater challenges. Therefore, this paper establishes a power grid optimal dispatch model considering the stability constraints of large-scale HVDC infeed, and puts forward a HVDC tie-line power optimization mode that comprehensively considers clean energy consumption and economy of the sending-end and receiving-end power grids. The model can consider the HVDC adjustment capacity and adjustment cost of the sending-end grid, the adjustment capacity and consumption demand of various resources such as wind, thermal and hydro in the receiving-end grid, safety and stability constraints on the coupling relationship between the HVDC transmission power and the startup mode of thermal units in the receiving-end power grid. By optimizing and adjusting the power of the HVDC tie-line, the model takes into account the operating economy of the sending-end power grid, the safety, stability and the demand for clean energy consumption of the receiving-end power grid. Based on the actual operating data of a domestic power grid, the validity of the established model is verified.