With the increasing of the HVDC system, large-scale AC/DC hybrid power system gradually becomes the basic form of Chinese power grid transmission. It also puts forward new requirements to analyze the stability and optimize the control method. This paper presents an optimized scheme of the under-voltage load shedding for AC/DC hybrid systems with static voltage stability index as constraint. Firstly, the static voltage stability index of AC/DC transmission is established based on the alternating current iteration method. Secondly, in order to make the load loss minimized, the optimal load allocation strategy is solved based on the improved genetic algorithm. The simulation results show that the new algorithm can optimize the control strategy, maintain the stability of the system, and reduce the loss cost.