In the process of architectural modeling and decoration designing, it needs different softwares to finish 3D modeling, effect drawing, animation, the material statistics and the 2D drawing; It is a real difficult problem to combine the several different simulation procedures in only one system. This article does some research on computer aided system of decoration, discourses the current application situation of the decoration software, discusses the basic system simulation theory, introduces the frame about computer aided system of decoration, and describes several important technology measures. At last, it validates the validity of this simulation system using the real applications. The system successfully integrates several functions including 3D modeling, drawing, animation, mixing scene, sticking picture, which satisfied the needs of designers. Meanwhile the system has been widely used for designing as a commercial software, and enhances the whole work efficiency of architecture and decoration designing.