Abstract: In southwest China, there are superior conditions of power generation. Making good use of the complementary characteristics of hydropower and photovoltaic power there is one of effective ways to achieve the "dual carbon" goal and promote the consumption of renewable energy. However, as the hydropower resources are generally distributed in the remote areas, long-distance power transmissions may increase a rather weak connection with the main network with a hidden dangerous of transient power angle stability. Besides, the high proportion of photovoltaic power generation also increases the complexity of the transient stability of the system. At present, there is not a clear mechanism to explain photovoltaic power generation's influence on the transient stability of complementary systems, and not an effective system emergency control methods based on quantitative calculations. To this end, this paper proposes an emergency generator tripping control method for improving transient power angle stability. Firstly, the equivalent power angle curve of the integrated system is established, analyzing the changes of the acceleration/deceleration areas in the integrated system before and after the photovoltaic connection. Subsequently, based on the equal area criterion, three emergency generator tripping control schemes for hydropower and photovoltaic coordination are proposed, and the optimal scheme is selected according to the comprehensive evaluation indexes. Finally, the effectiveness of the proposed method is verified based on the single hydropower generation and single photovoltaic generation-infinity system and the integrated system of Sichuan province.