The invention relates to an MEMS technology based micro liquid level metering device and a method thereof. The micro liquid level metering device comprises a gas tight pipeline and an MEMS micro structure pressure sensor; a PI pipe of the sensor is communicated to the atmosphere; a P2 pipe is connected with the gas-tight pipeline; the sensor measures the pressure difference between the atmosphereand gas in the gas-tight pipeline and outputs the pressure difference; and the volume of the metered liquid can be calculated according to the pressure difference.