Abstract: The effect of the turbine exhaust pipe on flow structure and aerodynamic heating of the rocket base was investigated by numerical simulation of the four-nozzle liquid rocket with and without turbine exhaust pipe. Based on the three-dimensional multi-component Navier-Stokes equation, RNG k-ε two-equation turbulence model and thermal radiation equation, the gas jet model of the rocket in the high-altitude flight phase was established by using the second-order upwind TVD scheme, and the numerical results were compared with the experimental data to verify the chosen model and calculation method. The study shows that the turbine exhaust pipe can change the temperature field and flow structure of the rocket base. As the altitude increases, the turbine exhaust pipe can effectively reduce the convection heating rate of the rocket base, thus playing a role in reducing the temperature. Compared with the rocket without turbine exhaust pipe, the pressure near the rocket base is slightly reduced, and there is a tendency to expand toward the area where the turbine exhaust pipe is installed.