The radar cross section (RCS) is one of the main parameters to measure stealth performances of a target. The RCS calculation is an efficient method to obtain the RCS of target. It has been widely used because of short period and high flexibility in the stealth technology. The process of RCS calculation is: Firstly, the geometric model of target is dispersed into mesh model combined by simple shapes such as triangles and then the RCS of mesh model is calculated. Therefore, whether the mesh model could enable to reflect the target shape or not directly relates to the calculation accuracy of RCS and can be judged by shape parameters of mesh elements (i.e., mesh parameters). In this paper, the RCS of different mesh models for different target models are calculated and then the influence rules of mesh parameters on RCS calculation is obtained. The rules provide a basic guidance for how to disperse the target model into mesh model.