The invention discloses a compressed gas drive liquid flow calibration device and a calibration method thereof. The calibration device comprises at least one set of gas-liquid replacement tank, liquid storage tank, liquid adding pump, gas storage tank, collecting container and weighing device which alternately work. A to-be-measured flowmeter, a thermometer, a flow adjusting valve and an indicating flowmeter are mounted on a liquid outlet pipeline. Switching valves are arranged on branches of a liquid inlet pipe, the liquid outlet pipe and a ventilating pipe. The calibration method comprises the following steps that gas pressure is pre-adjusted; liquid is injected; gas-liquid replacement is carried out, stable flow is generated, and a metering function is completed. The compressed gas drive liquid gas calibration device and the calibration method thereof have the advantages that the space requirement of the method is equivalent to that of a container pressure stabilizing method, a relatively closed structure can be formed, and the method is suitable for volatile fluid; the mechanism of guaranteeing flow stability is equivalent to that of a constant waterhead high position overflow tower method, the aim of combining the advantages of the two methods is achieved, and a manufactured liquid flow standard device can be used for the compressed gas drive liquid gas calibration device for calibration of a high-accuracy flowmeter.