The assembly test line applies the double-speed chain to convey the materials between stations. It adopts the twodimensional code to trace the data in the whole process, which combines the feeding technologies such as tower feeding, vibration feeding, slicing feeding and tube feeding to ensure the material supply; It uses visual guidance technology for positioning, realizes accurate assembly through servo press-fitting system and automatic tightening control system, and assist with 2D/3D visual inspection technology to detect incoming defects and monitor process quality in the assembly process; It realizes automatic laser two-dimensional code marking and scanning, servo automatic pressing of clamp spring, one-way valve and control coil, automatic oiling assembly and inspection of sealing ring, automatic tightening of electronic expansion valve, refrigerant valve and electromagnetic valve, and automatic assembly of drying device and heat exchange device. It also guarantees the stability of the production output and the improvement of the quality.