A new method to evaluate camouflage effectiveness by using the fractal character of infrared image was put forward. Infrared images of the object before and after camouflage were obtained. The fractal characters of the object and six around backgrounds before and after camouflage through Covering-Blanket were calculated. The comparability between the object and around backgrounds by the difference of their fractal characters was analyzed. The experiment result shows that comparability of the object and natural background before and after camouflage is enhanced, and the fraction is available to evaluate camouflage effectiveness.