The present invention provides a device for measuring air tightness of an aluminum alloy hub or a tire and a method for measuring the air tightness of the aluminum alloy hub or the tire by using the device. The device includes a pressure measurement device mounted into a hub or tire to be measured, an inflation device in gas connection with an inside of a tire of a wheel to be measured, and a data acquiring and processing device; wherein the inflation device includes a flow measurement component.