This paper studied the nonlinear dynamics of deploying cantilever laminated composite plates subjected to transversal aerodynamic pressures and in-plane excitations. The first-order piston theory was employed to model the transversal air pressures. Based on Reddy′s third-order shear deformable plate theory and Hamilton Principal, the nonlinear governing equations of motion were established for the deploying cantilever laminated composite plates. By choosing suitable vibration mode-shape functions, the two-degree-of-freedom nonlinear governing equations of motion with time-varying coefficients were deduced by using Galerkin method. The influences of varying deploying velocities on the nonlinear resonance of the deploying cantilever plate were analyzed.