The objective of this investigation is to study the rapid forming based on robot GMAW forming. The work may be divided into two sections. First study the modeling of weld bead profile. Self adaptive layered algorithm of variable direction is employed, which changes the forming direction on the basis of parts geometric character. In addition, the microstructure and performance characteristics of the formed parts are investigated. Its metallographic microstructure along the deposition direction shows obviously layered characteristic. The micro hardness values closely relate to the microstructure characteristics. The fracture mechanism of the part belongs to quasi-cleavage crack.