In order to solve the problems of single camouflage effectiveness evaluation method and insufficient quantitative analysis method, the cosine similarity principle was introduced to carry out simulation evaluation, and the theoretical analysis of visible light camouflage effectiveness evaluation was optimized. Based on the characteristics of color optical data, color histogram was used to show the color frequency distribution of target and background, and the difference of color fusion between sample target and background was studied. The luminance spatial characteristics were shown by luminance spatial distribution map, the luminance difference between the sample target and the background was explored. By collecting and calculating the pixel data of the target and the background image, the fusion effect of the target and the background was quantified. Based on the typical verification example, the correctness of the evaluation method was verified through the positive and negative comparative analysis. The results show that the cosine of the included angle between the image feature vector of the target and the background is 0.9982, and the fusion effect of the cosine similarity between the target and the background is respectively 0.9821 and 0.7324 by positive and negative comparison. Qualitative analysis and quantitative calculation show that cosine similarity theory can provide relevant algorithm support for camouflage effectiveness judgment and has certain practical value and application value.