Abstract: The polygonal base of prismoid is decomposed into quadrangles, the quadrangular vertices are located by using the node constraint principle and isoparametric smoothing scheme. Along the height direction, each prismoid is sliced into parallel layers. Through four-corner-point bilinear interpolation, inverse mapping of arbitrary point between two polygonal domains is established. Finite element meshes are generated automatically by combining the above schemes with transfinite mapping method and layered principle. This algorithm extends the application of transfinite mapping method. Results of test examples show the effectiveness and robustness of proposed algorithm.