The invention provides an automatic tray conveying system for a chip burning machine, and the automatic tray conveying system can solve the problems that an existing tray feeding device integrated with a chip burning machine occupies a large amount of chip burning machine space, consequently, the size of the burning machine is large, and universality is poor. The transverse front side end of a rectangular box is detachably arranged on the tabletop of the chip burning machine, and the two longitudinal side walls of the rear side end of the rectangular box are provided with symmetric three pairsof stand columns correspondingly. The three pairs of stand columns partition the upper space of the transverse rear side end of the rectangular box into a good product tray area and a supply tray area from back to front. The two longitudinal side walls of the part, located in the good product tray area, of the rectangular box are provided with symmetric good product tray supporting mechanisms, and the two longitudinal side walls of the part, located in the supply tray area, of the rectangular box are provided with symmetric supply tray supporting mechanisms. A transverse horizontal movement mechanism is arranged in the rectangular box, a tray bearing plate is vertically movably arranged on the transverse horizontal movement mechanism, and the transverse horizontal movement mechanism can drive the tray bearing plate to do the transverse horizontal reciprocating motion in the rectangular box.