Abstract: This paper introduces the analysis and pattern synthesis of some kinds of complicated base station antennas using genetic algorithm. The antenna approximated with wire grid is analyzed in terms of method of moment and synthesized using genetic algorithm based on the pattern demand. Through the proper choice of target function, the gain, beamwidth and backlobe are comprehensively considered during optimizing. The method can be used to analyze other array of the same kind with different radiating elements. The result is very useful for engineering and theoretic analysis.