The engine assembly line mainly includes assembly line, sub-assembly line, station equipment and online tools. On the assembly line and the sub-assembly line, forced or flexible conveyor lines are commonly used inChina, and automated assembly equipment is deployed on-line to improve efficiency. The forced conveying line is mainly a plate chain conveying line equipped with an assembly fixture. The flexible conveyor line mainly includes: differential chain line and power roller line. The automatic equipment on the assembly line mainly includes automatic marking machine, tightening machine, automatic turning machine and other special assembly equipment, which can greatly improve the assembly capacity of the assembly line.