The utility model relate to a coupling overload protection structure, in particular to an end face tooth (or axial tooth) structure. The coupling overload protection structure comprises an adapter plate, a flexible element and an adapter shaft and is characterized in that the adapter plate and the adapter shaft are provided with end face teeth; the flexible element is connected to the adapter plate and the adapter shaft in a staggered manner by bolts; and the end face teeth on the adapter plate and the adapter shaft can be joggled with each other to transfer torque. The coupling overload protection structure is simple and reasonable and has the function of double-path transmission protection due to the addition of the end face tooth structures on the original components. The coupling overload protection structure can effectively protect the flexible element and improve the reliability of a coupling. When the flexible element is out of commission, the coupling overload protection structure can replace the flexible element to transfer the torque for a short time, thereby preventing the over-speed phenomenon of a machine set.