Abstract: An ant colony algorithm is presented for infrared image segmentation. The core idea is to use the fuzzy membership function as enlightening information, which guides the ant colony with the pheromone together. By updating the distribution of pheromones on the routes that the ants have passed, the pheromones on the target route are increased, and the searching routes will converge on the segmented image progressively. Finally, the segmentation results can be extracted according to the intensity of the pheromones. Simulations and experiments show that the infrared image can be segmented well.