The invention discloses an assembling system of semi-circular pipes with welding rings. The assembling system of the semi-circular pipes with the welding rings comprises a material supplying device, atransmission positioning device and a robot inserting device, the material supplying device comprises a vibrating conveying mechanism, a distributing and isolating mechanism, a jacking material taking mechanism and a shaping and rectifying mechanism, and the transmission positioning device comprises a first conveying line, a transmitting part and a second conveying line. The robot inserting device comprises a four-axis robot, a clamping jaw fixing seat, a clamping jaw air cylinder and a floating clamping jaw. According to the assembling system of the semi-circular pipes with the welding rings, through the material supplying device, the efficiency of sleeving of the semi-ring-shaped copper pipes with the welding rings is improved, meanwhile through the robot inserting device, the semi-circular pipes sleeved with the welding rings by the material supplying device are accurately inserted on fins, a manual assembling mode is avoided, and thus the assembling efficiency of the semi-circularpipes with the welding rings is improved.