Solar-powered airships rely on photovoltaic (PV) array to provide energy, but the non-uniform illumination caused by the curved surface leads to energy loss of PV array. Genetic algorithm is introduced into the research of PV array optimization. By optimizing the topology of the PV array, the mismatch losses between PV modules are reduced and therefore the purpose of increasing the output power is achieved. Firstly, based on the single diode model of PV cell, the simulation method of PV array is given. Secondly, an optimization method based on genetic algorithm for PV array topology is proposed. By coding sequence, PV array topology is converted into chromosome coding, and PV array topology is optimized by the crossover and mutation of chromosome. Taking a solar airship as an example, the simulation shows that the average output power of the PV array increases by 2.32% after optimization. The simulation results show that the proposed method can effectively improve the output power of the PV array.