In order to improve the accuracy of simulation analysis of plate structural- acoustic coupling systems, the finite element-least square point interpolation method (FE-LSPIM) was extended to solve the plate structural- -acoustic coupling problems and a coupled FE-LSPIM/FE-LSPIM method for the analysis of plate structural- acoustic coupling systems was proposed. In the proposed method, the shape functions of the finite element method and the least square point interpolation method were used for local approximation; the compatibility properties of finite element method and the quadratic polynomial completeness properties of LSPIM were inherited. Thus the accuracy of simulation analysis can be improved. Numerical example of a box structural- acoustic coupled model was presented, which shows that the FE-LSPIM/FE-LSPIM method achieves higher accuracy as compared with FEM/ FEM and SFEM/ FEM for the analysis of plate structural - acoustic coupling problems.