Abstract: Using a general analytical solution of a plate, the vibration problem of rectangular plates with mixed boundary conditions has been solved. The general analytical solution of a plate can be used to solve vibration problem of rectangular plates with arbitrary boundary conditions of all edges. The procedure for rectangular plates mixed boundary conditions is dividing the plate into several plates. For each plate there are only uniform edges. The connected edges between two plates, there are continuous conditions. To make use all of the boundary conditions and continuous conditions, it can be solved each natural frequencies and vibration modes. For some plates with mixed boundary conditions of simply supported, clamped or free edges have been calculated and compared the results with other references.