The pintle valve is currently the most promising technology among all thrust control methods for solid rocket motors. Pintle structure and working condition play a critical role in the successful operation of a pintle motor. Here, 2D transient simulations of a pintle motor using dynamic meshing are performed. Reynolds-averaged Navier–Stokes equations are solved with the implementation of an RNG k–εturbulence model. In cold flow test, emphasis is placed on the effect of pintle structure, and in hot flow test, emphasis is placed on the effect of propellant pressure expo-nent. Validation is performed first by comparing the present results with available cold-test exper-imental data. This shows that the transient simulations can provide good predictions for pintle motors with a relative error of less than 2％in terms of the chamber pressure. It can be found that, when the gas supply system is different, the working principles and conditions of pintle motors are different. The feedback process in propellant combustion has a significant impact on its operation and the effect on the pintle motor performance of different pintle structures is achieved by different variations in the equivalent throat area. Finally, the pressure exponent is an important parameter in hot flow test and changes of thrust in hot flow test are not monotonic, because changes in the flow field and motor performance are asynchronous.