Existing image segmentation algorithm has the problems of large calculation amount and poor segmentation effect. Aiming at these problems,according to target segmentation characteristics of grayscale gradient two dimensional histogram,an infrared image segmentation algorithm based on ant colony algorithm and two dimensional histogram is proposed. The edges and noise correlation values are introduced into the traditional gray gradient two dimensional histogram. In order to extract infrared target rapidly,the image is divided into small windows,and the heuristic function and pheromone update function are redefined according to the optimal segmentation threshold. Experimental results show that the edge of infrared target is clear. The algorithm has a stronger anti jamming capability and faster computing speed.