Numerical simulation with discrete phase model was made on scramjet combustor of five strut-cavity structures to study the influence of strut tail structure on the mixture characteristics of kerosene/air. The impacts to mixing performance, vortex structures and total pressure recoveries were obtained. Results showed that staggered slope plates and staggered wedge plates could improve the mixing efficiency of kerosene component, but it also brought greater resistance and total pressure loss. The wedge-shaped block with a small number of blocks was more prone to large-scale and large-energy streamwise vortex, which can effectively extend the combustible mixed zone. The wedge-shaped block with a large number of blocks was more conducive to the small scale mixing in the near field, but was not dominant in large scale mixing in the far field.