In order to analyze the influence of pylon’s length, width, height to flow characteristics in the supersonic combustion, orthogonal experimental design method has been carried out to design different combinations of pylon size. By numerical simulation, the differences between different examples’ mixing efficiency, total pressure loss ratio, penetration depth has been contrastive analyzed. By intuitive method and ANOVA, it shows that height is the greatest influence on mixing efficiency, then the width, length is the worst. The size of pylon dose not have significant association with total pressure loss and penetration depth. The mixing efficiency of The optimized case(0-712439) is higher than any cases of this paper, and its total pressure loss(0-1303) lose 2％ for improving 37％ mixing, and penetration depth(10-023) lose 1％ for improving 9％ mixing. This paper provides a method reference for the designing and improvement of pylon.