The invention discloses a wire harness welding machine, which comprises a base, a material placing frame, a motor and a welding machine body. The wire harness welding machine is characterized in that the material placing frame is arranged on the base, a support shaft is arranged on the top of the material placing frame, the back end of the material placing frame is provided with the motor, the front end of the material placing frame is provided with a driving press wheel and a driven press wheel, the motor drives the driving press wheel and the driven press wheel to rotate, a carrier table is arranged at the side surface of the material placing frame, a moving frame is arranged at the back end of the carrier table and can slide along a guide rail, a clamping air cylinder is arranged on the moving frame, the clamping air cylinder controls a clamp claw to tightly clamp tin wires, a welding machine body is arranged at the back end of the moving frame, and a welding head is arranged on the welding machine body. The wire harness welding machine solves the problems that a wire harness and a connector are welded, the tin wires can easily rotate, the welding precision is low, the tin consumption is great, the tin adhesion is not uniform enough, and in addition, the tin wires can easily fracture and can be easily damaged in the processing process. The invention provides the wire harness welding machine with the advantages that the processing is convenient, the welding precision is improved, the tin wire consumption is reduced, and the cost is reduced.