To analyze flow characteristics of the cantilevered ramp injector in supersonic combustion, the numerical simulation was carried out to investigate the effects of cantilevered ramp injector on ethylene injection. Several conditions were carried to analysis about the influence, such as: with and without cantilevered, swept structure and unswept structure, different kinds of cantilevered structure. It is found that the cantilevered ramp structure can enhance the mixing effects and increase penetration depth, comparing with ramp injectors. Swept structure can effectively enhance the streamwise vorticity in the flow field, so as to enhance the mixing effects, but also bring higher total pressure loss. Triangular cantilevered structure can’t enhance the streamwise vorticity, and so as not to enhance the mixing effects, but bring lower total pressure loss. There is no obvious difference between two kinds of swept cantilevered ramp structure’s flow fields.