Abstract: In order to improve the electromagnetic monitoring performance of the electric patrol UAV（unmanned aerial vehide）, an optimization method of elliptical array antenna for UAV electric patrol is introduced in this paper. The array elements of the array antenna are arranged uniformly which can reduce the number of the array elements and the number of the feed terminal unit while ensuring the performance of array antenna. Each array element is fed at equal amplitude, which can reduce the design complexity of the feeding network. So the power consumption of the array antenna is reduced to a certain extent, and the patrol time of the UAV is improved. The positions of the array elements are optimized by the modified optimization method and the radiation pattern with minimum peak sidelobe level（PSLL） is obtained. Therefore, the array antenna can reduce the impact of the environmental noise effectively. The simulation result shows that the method proposed in this paper can reduce the PSLL of the radiation pattern while the element number of the array antenna, the minimum spacing of the adjacent elements and the size of the array antenna are given. The PSLL of the radiation pattern is lower than-24 dB when the element number of the elliptical array antenna is 41.