This paper has studied the defects and deficiencies of corner welder in the domestic and overseas,and has designed a corner welder with solving welding blind area and welding seam tracking. The STM32 single-chip was taken as the controller of the angle welding machine. Step-by-steps electrical machinery was used as the actuation functional element. Finally,through the reasonable mechanical structure,the transformation of traditional angle welding machine was realized. The test welding of the angle welder shows that the weld has no joint length,uniform molding uniformity,simplified operation and improved welding efficiency.