Hybrid methods are commonly methods to solve the response of mid-frequency vibro-acoustic system. In this study, a novel hybrid CSRPIM/SEA method is proposed to calculate the coupling problem between enclosed cavity and flexible plate. Deterministic subsystem with low modal density is modeled by the Cell-based Smoothed Radial Point Interpolation Method (CSRPIM) and statistical subsystem with the high modal density is modeled by the Statistical Energy Analysis (SEA). Owing to the generalized gradient smoothing technique and the condensed shape function technique used, the stiffness of discrete model is softened and the dispersion error can be reduced obviously, which makes the hybrid CSRPIM/SEA method give satisfactory numerical results considering the examples studied. The proposed method has provided an effective way for analyzing mid-frequency virbo-acoustic problems.