The spray painting assembly line forms a closed-loop series of pre-treatment, spray painting, curing and other processes through a conveyor line. After cleaning the workpiece, it undergoes spray painting treatment, and after curing, a coating is formed on the surface, which plays a role in rust prevention, corrosion prevention, and aesthetics. At the same time, individual operation equipment on the spray painting assembly line can also operate independently as a system. This equipment is suitable for surface treatment of most substances such as metal products, glass products, wood products, plastic products, etc