For the purpose of accurate inspecting IC chip by image, fuzzy gray theory is used for quantitative evaluating the IC micro-topography’s influence on its image characteristics. Through extracting topography’s feature-points by precise coordinate measuring apparatus, its spatial surface model is structured and the topography characteristic parameters array is established, thus a mathematical model of fuzzy gray evaluating system is obtained. After calculating the fuzzy gray relational degree between the topography characteristics and the image ones, the influence has been quantified. By experiment repeatedly the influence discipline is analyzed and the conclusions are reached. It provides theoretical foundation and technical preparation for IC image sampling condition’s selection and adjustment.