Abstract: In order to explore the effect of pixel's geometry shape in photoelectric imaging sensor on imaging quality, mutual information was used to analyze the imaging quality with rectangle pixel array and hexagon pixel array. System simulation with noise interference has been done and the superiority of different pixel's shapes was analyzed. Results show that, for the same area, the mutual information of hexagon pixel is greater than rectangle pixel, and the hexagon pixel array has strong ability to restrain the noise interference. The advantages of hexagon pixel have important significance on development and evaluation to the optoelectronic countermeasure equipment.