High proportion of photoelectric (PV) penetration will aggravate the difficulty of source-load coordination in the Hydro-PV complementary system and cause the risk of power fluctuation and curtailment. Therefore, a day-ahead optimal scheduling method considering source-load coordination was proposed. Firstly, the qualitative features were extracted based on the PV waveform segmentation and power partition, and the coupled cloud was introduced to simulate PV power uncertainty scenarios. Subsequently, the evaluation indexes of power fluctuation and curtailment were selected to establish the day-ahead scheduling model. Additionally, the waveform hierarchical compensation strategy was adopted to guarantee load tracking capability and control power curtailment risk, and then the generation plan was prepared. Finally, the real-time operation effect of the system was analyzed according to the real scenario set in the actual case. The results show that the coupled cloud model can simulate the PV power uncertainty with different robustness conservatism in two dimensions of waveform and power generation. Compared with the conventional deterministic optimization, the day-ahead optimal scheduling method can give full play to the flexibility of hydropower and reservoir regulation and has stronger risk bearing ability. Furthermore, the transmission form can meet the requirements of source-load coordination and avoid the risk of power curtailment effectively.