Based on the classical theory, and according to the structural features of SMA (stone matrix asphalt), this paper analyzes the road performance of SMA such as high-temperature stability, etc. The analytical result shows that good road performance of SMA comes from its structural characteristics. Through analysis of SMA design methods adopted in different countries, The tests are carried out in the following procedures: this paper has studied aggregate gradation to ensure which kind of coarse aggregates contributes more for high-temperature stability. The coarse aggregate of equal size is used as sample to do Marshall test (Asphalt compound test ) and rutting test. According to the analysis of test results, it is difficult to decide which kind of coarse aggregates does more contribution for high-temperature stability of SMA, and therefore, comprehensive analysis should be made on coarse aggregates of different grades so as to achieve satisfactory result.