Abstract: A coordinate transformation method is presented,which facilitates the numerical evaluation of the integrals involved in the 3-D FEM-BEM hybrid method based on Whitney 1-forms.The integral domain is mapped to a unit square region from any arbitrary triangular region,or to a unit cubic region from any arbitrary tetrahedral region by introducing three coordinate transformations.So the integrals involved in the hybrid method can be computed conveniently by Gauss-Legendre formulation.And the method is verified by numerical experiments.