Abstract: To investigate the impact of gaseous kerosene on the mixing and combustion performance of a scramjet combustor with pulsed injection, the two-dimensional RANS equations are solved using the two-equation k–ω SST turbulence model. The flow field structure of the scramjet model with the cavity and backward step as the flame stabilizer under the condition of Mach 2.5 inflow, total pressure of 1.75 MPa, and total temperature of 1350 K is investigated. The mixing and combustion performance of kerosene and air under steady injection and pulsed injection are compared and analyzed. The results show that the simulated schlieren pattern is in good agreement with the test, only 0.2 ms earlier than the test, accounting for 2.89% of an oscillation period (6.9 ms). Pulsed injection results in a prolonged existence of the recirculation zone within the combustion chamber cavity, enhancing fuel retention in this region. It is not found that the pulsed injection has a significant contribution to the total pressure loss, while the temperature and pressure distribution of the pulsed injection is uniform without the thermo-dynamic throat.