Based on the time-series production simulation method which takes into account the time-series variation characteristics of system load and power generation output of new energy, the time-series production simulation model of hydro-optical power system is established. The optimal water-light capacity ratio is determined comprehensively from the aspects of system structure, economy, flexibility and reliability, and the rationality of the model is verified by the water-light system of the upper reaches of the Jinsha River in the Sichuan-Tibet section. The outputs of photovoltaic power stations and hydropower stations in the upper reaches of the Jinsha River are complementary within a year and within a day. For the level year of 2030, considering the retention of hydropower during dry period, the comprehensive performance of 9.136 million kW hydropower with 4 million kW photovoltaic is better, and the new non-water renewable electricity is about 6 billion kW·h.