Composite sealing assembly, piston rod of hydrogen compressor, air cylinder assembly and compressor

The utility model discloses a composite sealing assembly, a hydrogen compressor piston rod, a cylinder assembly and a compressor, the sealing assembly comprises a packing box, the packing box is provided with a center hole and packing grooves, each packing groove is internally provided with sealing packing, and flexible packing is arranged in the packing grooves and part of the packing grooves. Part of the packing grooves are internally provided with packing rings. The device further comprises a hydraulic oil circulating device. The hydraulic oil circulating device comprises an oil pump and a circulating pipeline and further comprises a back pressure valve, a surge tank and a one-way valve which are connected to the circulating pipeline in series. A packing groove for mounting flexible packing is connected in series on the circulating pipeline between the outlet of the surge tank and the inlet of the back pressure valve; and the pressure measuring assembly is used for measuring the pressure in the surge tank.