In order to improve the electromagnetic monitoring performance of the electric patrol UAV and reduce the design difficulty of the feed network of the array antenna, an optimization method of elliptical antenna array for UAV electric patrol is introduced in this paper. The radiation pattern of the array antenna has low peak side lobe level (PSLL). So, the array antenna can reduce the impact of the environmental noise effectively. In order to the power consumption of the array antenna and improve the patrol time of the UAV, the array elements have the same excitation. The positions of the elements are optimized by modified optimization method and the radiation pattern with minimum peak side lobe level (PSLL) is obtained. The simulation result shows that the method proposed in this paper can reduce the PSLL of the radiation pattern. The PSLL of the radiation pattern is lower than -22dB when the element number of the elliptical antenna array is 41.