Parachute recovery is a common way of UAV recovery. As the first step of parachute recovery, parachute deployment process plays an important role. Parachute deployment is to pull the connecting belt through the continuous pulling force generated by the combustion of the rocket engine, so as to drive the parachute and the suspension line, and pull the parachute out of the parachute cabin. Based on the nonlinear finite element theory, the dynamic model of parachute deploying process is established by ABAQUS finite element simulation software, and the influence of rocket on the deploying process at -50℃、+20℃ and +55℃ are studied. The results show that with the increase of temperature, the deploying time becomes shorter, and the deploying length of canopy and parachute rope changed little, and the maximum tension of the connecting belt and the parachute rope becomes larger. The simulation results are compared with the experiments at +55℃, and the results are in good agreement with the simulation results, It can be seen that the dynamic model is suitable for the simulation of parachute deploying process.