Compared with vacuum tank system, supersonic injection technology has significant advantages in pressure recovery of chemical laser weapons, among them, the supersonic center injector has greater injection potential due to its smaller total pressure loss. Simulation and experimental studies were conducted on the supersonic center injector. The results show that for the supersonic center injector with a contraction-type mixing chamber, although it is easier to reach the working state, it is not superior to the straight-type injector under the condition of fixed injection coefficient and maintaining a lower blind cavity pressure. Under the condition of variable injection coefficient (fixed secondary mass flow rate), for every 0.05 increase in the area contraction ratio of the mixing chamber, the primary mass flow rate needs to be increased by approximately 0.3 kg/s to reach the critical start-up state. The overall injection performance of the supersonic injector reaches its highest when it is at the critical start-up state. In terms of blind cavity extraction capability, the single-stage supersonic center injector is significantly superior to other types of injectors, with a minimum of 1.3 kPa achievable.