An optimized model of circle array was set up from the basic optical synthesis aperture circle-array imaging principle. The sub-apertures array was optimized by adopting genetic algorithm with an improved real coding method coding the location of sub-apertures array. The objective function was designed by maximizing the distances between u-v coverage dots and minimizing redundant array. The point spread function, optical transfer function and diffractive imaging of two-dimensional (2D) circle array synthetic aperture imaging system were analyzed. The optimized result of 8～16 sub-apertures on a two-dimensional circle array was obtained and compared with the result by simulated annealing algorithm. Using the emulator program, the point spread function was analyzed and contrasted to that of a uniform circle array. Results show that the improved real coding genetic algorithm can resolve the synthesis aperture array optimization well, cost less time and get an even better optimization compared with simulated annealing algorithm.