Abstract: Complementation among cascade hydropower stations and photovoltaic is of great significance for stabilizing photovoltaic fluctuations and improving photovoltaic consumption. For this reason, firstly, starting form the two objective functions, i.e., minimum fluctuation of generated power and maximum economic benefit of power generation, considering the participation of hydro-photovoltaic complementary system into power grid active power balance auxiliary service, by means of setting the design value of hydro-photovoltaic complementary system to make its intraday output trend enable to fallow the fluctuation of power network load in a short-term multi-objective certain range, a multi-objective optimal dispatching model of short-term cascade hydro-photovoltaic (abbr. PV) complementary system was established. Secondly, taking the water volume constraint of cascade hydropower stations and typical daily power generation characteristics of three typical intraday sunny, cloudy and rainy photovoltaic power stations into account, a multi-objective evolutionary algorithm based on decomposition was used to solve the problem. Finally, the intraday optimal scheduling of the cascaded hydro-photovoltaic complementary system under three typical scenarios is verified and analyzed. The results show that the cascaded hydro-photovoltaic complementary system can effectively suppress the intermittency and volatility of photovoltaic power generation, and the output of the complementary system can be adjusted in time during the peak load period of the grid. The optimal scheduling scheme of the complementary system takes into account both power fluctuation and economic benefits of power generation.