When heavy equipment are airdropped, the cabin cross-section is largely blocked, and rapid moving of heavy equipment will cause drastic changes in cabin pressure and even damage the health of cabin crew. Therefore, it is necessary to carry out numerical simulation of the pressure change in the airdrop cabin of the transport aircraft, and to lay a foundation for further research. In this paper, the fluid-solid coupling problem of variable acceleration linear motion in x direction under the combined action of traction pull of parachute, gravity, friction and aerodynamic force in the cabin of transport aircraft is taken as the research object, based on the motion overset grid. Numerical simulation of dynamic pressure variation in the forward compartment of a transport aircraft with heavy load airdrop is carried out. The results show that:(1) the closer the airdrop object from the frontal wall cabin, the higher the flow velocity and the bigger the degree of cabin cross-section blockage, the bigger the dynamic pressure change in cabin, and vice versa. (2) In the wind tunnel test, non-dimensional cabin pressure with reference of the front cabin pressure at the airdrop beginning is the most accurate and appropriate cabin pressure similarity criterion.