Abstract: When FEM is used to analyze the structures that include plate-like joint interfaces, the effect of plates on joint interfaces is often be ignored and defect thus follows. Aiming at the traditional method for calculating the stiffness of plate-like joint, this defect is revised and a comprehensive unit stiffness matrix is deduced. The matrix can be applied to finite element analysis and identities of dynamic characteristic parameters of joint interfaces. By comparing the results of presented method and the traditional method through an example, the former is proven to have higher accuracy and reliability. The presented method can be applied to modeling and analyzing of the similar structure and can be used as a way to solve mechanical vibration issues.