Abstract: The effect of the element shape on the element stiffness matrix of thin shear plate is considered and the shape factor with the vector method is computed when designing the structure analysis program with the finite element method. The choice of Gauss Integration Points in the numerical integration is also considered in order to improve the calculating accuracy and decrease the cost of computation. An element stiffness matrix of quadrilateral bent plate which is solved with the Guass Integration is derived. In the stiffness matrix superimposition, the sixth degree of freedom grid is introduced and the spectial coefficient matrix is employed, so that the general stiffness matrix singularity can be avoided as the elements are coplauar. Two practical examples show that these methods are effective.

Key words: shear factor, F, E, Programing, composites