The invention discloses a portable vehicle air inflation device comprising an air storage tank, a decompression integrated valve arranged at the upper end of the air storage tank, and an air inflation device connected with the decompression integrated valve. The decompression integrated valve comprises a valve body matched with the upper end of the air storage tank in a nested mode, an adjusting nut, a valve element spring, a valve element, a sleeve arranged on the outer side of the valve body in a nested mode, wherein the adjusting nut, the valve element spring and the valve element are sequentially arranged in the valve body from bottom to top. The air inflation device comprises an air inflation hose connected with the decompression integrated valve and an air inflation nozzle arranged at the end of the air inflation hose. According to the portable vehicle air inflation device, compared with a traditional tire pump, using is convenient and fast, time and force are saved; compared with an electric air inflation pump, the portable vehicle air inflation device has the advantages of wide using range, long service life, low price and the like; and meanwhile, the portable vehicle air inflation device can be used for vehicles such as a bicycle and an electric vehicle which cannot use electric air inflation pump , and the effect is superior to the electric air inflation pump.