Abstract: A dimensionality reduction method based on modified genetic algorithm is presented under the constraints of fixing the aperture, the number of elements and the minimum element spacing. In order to utilize effectively the freedom of array element, the proposed method transforms the positions of two-dimensional concentric rings array optimization design into one-dimensional linear array when sparse array meet multiple optimization constraints, and then restore to the concentric rings array when calculating its performance. The proposed method reduces greatly the computation time and the complexity of the model. Meanwhile, due to the combined optimization of all elements, the optimization design is improved. Simulation results demonstrate the effectiveness of the proposed method.