Mesh transition, an ordinary method is utilized to realize the non-uniform grid division of weld area,HAZ and base metal zone in order to assure the precision and efficiency of finite element modeling in welding process,which is the major cause of more meshing time and bad efficiency. Based on the model of mesh transition,a butt-joint transition algorithm is compiled by the secondary development of Hyper Mesh software in the use of TCL/TK language and visual interface operation is also realized. The example shows that less pre-processing and higher division efficiency can be achieved by the means of secondary development.