Abstract: Hydro-wind-solar complementary is one of the important ways to build a new power system and achieve the carbon peaking and carbon neutrality goals.By giving full play to the complementary characteristics of water energy, wind energy and solar energy in time and space, the consumption capacity and utilization efficiency of new energy can be effectively improved.The research progress of multi-objective optimal scheduling of hydro-wind-solar complementary system was systematically reviewed.Firstly, starting from the composition structure and coordination mechanism of hydro-wind-solar complementary system, the key role of cascade hydropower in stabilizing wind-solar output fluctuation and enhancing system regulation ability was deeply analyzed.Secondly, focusing on the modeling method, intelligent optimization algorithm and output uncertainty processing strategy analysis of multi-objective scheduling of hydro-wind-solar complementary system, the current research results and engineering practices in improving power generation efficiency, enhancing output stability and satisfying ecological constraints were summarized.Finally, in view of the problems and challenges existing in the research, the future research directions were discussed in order to provide a reference for the efficient utilization of Chinese scenery resources, the optimal development of clean energy bases and the transformation of energy structure.