The utility model relates to a protection device for a radiator assembly. The protection device comprises an oil radiator, a water radiator, an intercooler, an air director, an oil radiator protecting net, a water radiator protecting net, an intercooler protecting net and a frame. The oil radiator, the water radiator, the intercooler, the air director, the oil radiator protecting net, the water radiator protecting net and the intercooler protecting net are assembled and fixed on the frame. Due to the fact that the oil radiator protecting net is fixed at the front end of the oil radiator, the water radiator protecting net is fixed at the front end of the water radiator, and the intercooler protecting net is fixed at the front end of the intercooler, sundries can be effectively prevented from polluting an oil radiator core, a water radiator core and an intercooler core directly, service lives of the oil radiator core, the water radiator core and the intercooler core are prolonged, and reliability of the structure of the radiator assembly is improved.