The invention discloses a compressed air foam fire extinguishing device. The compressed air foam fire extinguishing device comprises a foam pump assembly, a water supply assembly, an air supply assembly, a mixing assembly, a control assembly, a linkage assembly and a clutch, wherein the water supply assembly comprises a fire pump, the air supply assembly comprises an air compressor, the linkage assembly is arranged between the fire pump and the air compressor, the clutch is arranged on a main shaft of the fire pump, and the control assembly pneumatically controls the clutch and controls contact and separation of the clutch and the linkage assembly. Through the contact and separation of the linkage assembly and the clutch, an outlet of the device can output water, mixed liquid or a compressed air foam extinguishing agent, so that the device can be applied to different fire behaviors, the applicability of the device is improved, and through separation of the linkage assembly and the clutch, when water or mixed liquid is output, the air compressor is prevented from idling, the air compressor is effectively protected, the working stability of the compressed air foam fire extinguishing device is guaranteed, and the fire extinguishing efficiency is improved.