The method of reverberation ray matrix (MRRM) is extended to research the transient wave propagation and early short time transient responses of the stiffened laminated composite plates subjected to impact loads. The rib-stiffened laminated plates are modeled as the coupling systems in which the flexural motion for the laminated plate is considered, and the flexural and torsional motions are taken into account for the laminated stiffeners, which are modeled as the beams. The dynamic models of the laminated plates and beams in the Laplace phase space are established based on the first order shear deformation theory (FSDT). The reverberation ray matrix is determined by the continuous and boundary conditions of the stiffened laminated plate. The transient response corresponding to each ray group is calculated by the FFT algorithm. From the numerical results, it is seen that the early short time transient accelerations of the stiffened laminated plates are very large, while the early short time transient displacements are very small. Furthermore, the influences of the stiffeners and different impulse signals on the early short time transient responses of the stiffened laminated plates are also studied.