Dryer, air pump, air suspension system and vehicle

The invention relates to the technical field of air pumps, in particular to a dryer, an air pump, an air suspension system and a vehicle, the dryer comprises a shell, the shell is provided with an inner cavity for storing a drying agent, and is provided with an inflation nozzle and an opening which are communicated with the inner cavity; the cavity wall of the inner cavity is provided with a blowback air channel, and the blowback air channel is respectively communicated with the inner cavity and a pressure relief nozzle arranged on the shell; when the dryer is installed, the back-blowing air channel is transversely arranged and located at the bottommost part of the gravity direction of the inner cavity. The device further comprises an opening and closing mechanism which is used for controlling the pressure relief nozzle to be communicated with or cut off from the blowback air channel. According to the dryer, an inner container is omitted, the structure and an air channel are simplified, meanwhile, the back-bl