<p>To improve the accuracy and efficiency of fluid–structure interaction calculation during the inflation process of flexible parafoils, Multi Zones Fluid Structure Interaction (MZ-FSI) numerical simulation method is proposed in this paper. The method takes into account the characteristic that the external pressure gradient of the parafoil cell is large, while the internal pressure is relatively uniform. The computational domain of the flow field is divided into two regions, the internal and external region, with the canopy structure as the boundary. The Ideal Gas State equation and Navier–Stokes equation are used to calculate internal and external flow fields, respectively. A numerical simulation of the parafoil inflation process is carried out based on the MZ-FSI method. The numerical results are in agreement with experimental results. On this basis, compared with the ALE method, calculation errors of projected area, projected span, and inverted dihedral angle of the canopy in the MZ-FSI method are reduced from 21.7%, 16.4%, 41.3% to 2.8%, 9.3%, and 2.5%, respectively. The inflated aerodynamic shape is closer to the actual situation. As well, pressure distribution, aerodynamic characteristics parameters and motion velocity parameters are simulated more accurately, which is conducive to accurate evaluation of parafoil aerodynamic and gliding flight performance. At the same time, the new MZ-FSI method is more efficient, saving 20.7% memory space and improving computational efficiency by 22.2%. The method presented in this paper provides a new analytical method for the study of parafoil opening performance and a new idea for numerical simulation of similar flexible flight structure’s inflation process.</p>