Abstract: To aim at the optimum design problem of sparse circular plane arrays with multiple constraints，the initial feasible solution which meet multiple design constraints can be made based on the position of uniform concentric circular arrays，and let this solution be the thinning chromosome which is presented for the distribution characteristic of the element position with circular boundary.An indirect representation of individual is presented，and a new crossover and mutation operator is designed.The improved genetic algorithm is used for optimization of sparse plane arrays with circular boundary.The multiple design constraints include the number of element，the aperture and the minimum element spacing，and the optimization objective is to make the sparse plane array produce lower peak sidelobe level (PSLL).A smaller solution space can be searched，the computing efficiency can be improved and the freedom of the element layout can be kept with this improved genetic algorithm.Finally，the simulated results confirming the great efficiency and the robustness of the new algorithm are shown in this paper.