Different types of surface morphology have different effects on multiple reflection of optical materials for absorbing light and have significant influence on absorptivity of materials. A suitable surface morphology can increase the effective absorptivity of optical materials. In this paper, we simulate the multiple reflection effects of V-shaped surface, Sine-shape surface, normal or uniform obliquity distribution surface and normal height distribution surface with the ray tracing method, and then analyse the capabilities of increasing the absorbtivity and the characteristics of incident angle of light on the four types of surfaces. The common necessary condition for increasing absorbtivity of these surfaces is obtained by obliquity analysis, i.e. the mean obliquity of the surface should be larger than 30 degrees at least, and the advantages of the V-shape surface to increase absorptivity under normal incidence are analysed.