The plane-folded deformed wing mechanism is a deformed wing mechanism that can accommodate both high and low speed conditions, which can realize the variation of wing chord, swept-back angle and wing area. The kinematic modeling of the unit mechanism is based on the structural composition of the plane-folded deformed wing unit mechanism, and the dynamics modeling of the unit mechanism is carried out by using the complex vector method and the D’Alembert’s principle. Matlab software is used to numerically calculate the dynamics model of the mechanism and plot the variation curves of velocity, acceleration and equilibrium force required by the mechanism. The numerical calculation results are compared with the Adams simulation results for analysis. The results show that the dynamics analysis of the unit module of the plane-folded deformed wing mechanism by applying D’Alembert’s principle can obtain the kinematic sub-constrained reaction force and equilibrium force of the mechanism in the deformation case. By comparing the results of theoretical calculation and simulation analysis, the correctness of the dynamics model of the plane-folded deformed wing mechanism is verified, which can provide theoretical reference for the in-depth study of the dynamics characteristics of the mechanism.