The method for measuring the liquid level in the oil tank can be divided into two types, namely, the measured height (the distance from the bottom of the tank bottom to the liquid level) and the height of the measured air (measured from the top of the tank to the liquid level). The actual value of the liquid level in the tank can be obtained by subtracting the height from the reference height (the vertical distance between the reference point and the measuring point). If the reference height is fixed, the measurement results of the two methods are consistent with the measured height and the measured air height. In the empty high school, referring to the height directly involved in the calculation of the results of the measurement, with reference to the changes in the height of the measurement of the impact of high school level measurement is obvious. At present, there is no national standard detection automatic tank liquid level meter, automatic detection of tank level gauge is not standardized, one of the more common is the use of the manual measurement of the liquid level meter for verification, another method is to use high accuracy liquid level gauge calibration another level meter