The utility model discloses a wiring harness welding machine. The wiring harness welding machine comprises a base, a discharge frame, a motor and a welding machine main body, and is characterized in that the discharge frame is arranged on the base; a support shaft is arranged on the top part of the discharge frame; the motor is arranged on the back end of the discharge frame; a primary pressing wheel and a secondary pressing wheel are arranged on the front end of the discharge frame; the motor drives the primary pressing wheel and the secondary pressing wheel to rotate; a carrier platform is arranged on one side face of the discharge frame; a moving frame is arranged on the back end of the carrier platform; the moving frame can slide along a guide rail; a clamping cylinder is arranged on the moving frame; the clamping cylinder controls a clamping claw to tightly clamp a tin wire; the welding machine main body is arranged on the back end of the moving frame; a welding head is arranged on the welding machine main body. The wiring harness welding machine solves the problems that the tin wire rotates easily when the wiring harness is welded with a connector, the welding precision is low, the tinning amount is great and is not uniform enough, and the tin wire is easy to break and damage in the processing process; the provided wiring harness welding machine is convenient to process, improves the welding precision, reduces the use amount of the tin wire and lowers the cost.