The 630 mm tray exchange mechanism was studied with the horizontal processing center as the parent machine,and its structure was also elaborated.Its main structure included installation base,support cavity,upper base,gear center shaft,exchange arm,hydraulic cylinder,hydraulic piston,spline shaft,etc.The swing cylinder drive tray switching mechanism took the hydraulic pressure as the driving force to achieve the lifting and rotation of the exchange mechanism.The lifting and rotation were achieved by combining piston structure,bearing and swing cylinder.The lifting process was completed by the piston structure,and the rotation process was completed by the swing cylinder.It is of such advantages as simple installation,high stability,high efficiency etc.