Aiming at the evaluation of camouflage effect，we start our study from the aspects of camouflage pattern intensity, color, texture, shape and size. We use the method of the control variables and fuzzy comprehensive evaluation to establish low visibility analysis model to analyze Low visibility effect of various patterns. We also establish camouflage effectiveness evaluation model based on similarity. By using the gradient method, we calculate the similarity of between camouflage and background to evaluate the effect of the camouflage.