The gas-particle inner flowfield of gas injection thrust vector nozzle in solid rocket engine was simulated using Euler-Lagrangian method,and the effect of solid particle on thrust vector performance was studied.The Roe scheme and monotone upstream-centred schemes for conservation laws(MUSCL)method were used for secondary-order accuracy spatial discretization for gas phase,and the implicit scheme was employed for time marching.The stochastic trajectory model and two-way coupled with gas phase were employed for particle phase.The results indicate that the strength of bow shock is increased due to solid particles,but the thrust vector angle and thrust coefficient are decreased;thrust vector angle and thrust coefficient increase with the particle diameter increasing under the same mass fraction of particle condition;thrust vector angle and thrust coefficient decrease with the mass fraction of particle increasing under the same particle diameter condition.