To reduce computational effort, raise the level of charging design, put forward a general solid rocket motor charging simulation algorithm. Through the secondary development of UG NX software tools BlockStyler, generated visual geometric model with common medicine type, used UG NX second development API SNAP for the coordinates of discrete points on the surface of normal data, etc. Used C++ language to simulate combustion process, a detailed discussion combustion went on line intersect, acquired methods for sharp corner processing and curve fitting, get meat thickness and burning surface area of the curve of the grain, compared analytic solution, the paper expounds the error reason exists, and the error was analyzed and processed. The results showed that the study concluded that a combustion simulation algorithm has a certain reference value for improving the solid rocket motor charging design precision and efficiency.