The numerical simulation of rough surface is research precondition and basis of contact capacity of engineering assemblies. Aim at the shortcoming in the simulation of rough surfaces, a new numerical simulation method of rough texture surface was proposed. The rough surface with desired auto-correlation function was simulated by the digital filter method, and the texture surface with desired parameters was simulated. After normalization of rough surface and texture surface, two surfaces were synthesized by adding the proportion coefficient in the texture surface, the rough texture surface was simulated. At last,two types of rough texture surfaces were simulated. It showed that the proposed method could simulate accurately all kinds of surfaces.