Abstract: Aiming at the problem of reaction control system (RCS) jet interference in Mars atmosphere, a self-developed CFD software was used to numerically simulate the jet interference effect of Mars Science Laboratory (MSL) shape in Mars atmosphere, and the results were compared and verified with those from calculation and from hypersonic jet interference wind tunnel test in the reference. Then, the numerical simulation of the yaw direction jet interference effect under hypersonic velocity (M_∞=5-10) in Mars atmosphere was completed. The aerodynamic laws of jet interference under different attack angles (from 0° to -30°) and different Mach numbers were obtained: a. The increase of negative attack angle leads to the increases both in jet interference effect and additional yaw moment; b. The incoming Mach number has little effect on additional moment. Those research may provide some reference for the design of Mars probe jet control.