The invention discloses an automatic tray-sucking machine. The automatic tray-sucking machine comprises a frame, a conveying device arranged on the frame, a storage rack located besides the conveying device, and a sucking device located below the storage rack and further comprises a transverse conveying device and a tidying device. The transverse conveying device is located below the storage rack. The tidying device is arranged behind the conveying device. The automatic tray-sucking machine has following beneficial effects: by optimizing the overall structure, food supports can orderly enter a conveyer belt after trays are sucked up and then subjected to food-loading operation in sequence in order to realize fully-automated operation, thereby reducing input in labor; meanwhile, the automatic tray-sucking machine is capable of optimizing mechanisms of all devices such that motion is performed reasonably and mechanical movement is carried out smoothly; and the automatic tray-sucking machine is used for support-separating equipment in the field of food production.