A C-band planar beam-forming array antenna which is serial parallel combined is designed in this paper. The feed amplitude and phase of array antenna are optimized by using Differential Evolution(DE)Algorithm, and the influence of mutual coupling on array is considered. The array is simulated and analyzed by the using of full-wave EM simulation software-HFSS, and the Patterns obtained are in a good agreement with the pre-numerical results. According to the results of simulation and optimization, the antenna array was produced and tested, and the testing result is consistent with the simulation result