The comprehensive similarity between the camouflage target and the background can measure the feature difference between the camouflage target and the surrounding background. The higher the comprehensive similarity, the higher the fusion degree between the target and the background, and the higher the camouflage efficiency of the target. In this paper, seven typical features of target and background images, including brightness, color, texture, shape, size, structure, and histogram, are used to represent the camouflage characteristics of the target. The corresponding similarity measurement method is used to obtain the similarity of each feature. The entropy weight method is used to objectively determine the weights of different feature indicators, and the comprehensive similarity between the camouflage target and background is obtained by linear weighting. Thus, the quantitative evaluation results of target camouflage effectiveness can be obtained. Multiple experiments under different backgrounds, different reconnaissance distances and different target attitudes show that the comprehensive similarity between the camouflage target and the background proposed in this paper is consistent with the target discovery probability, consistent with the detection distance, and robust to the background, which proves the correctness and effectiveness of the proposed method. The reliability of the proposed method is proved by comparison experiment.