Differential pressure controller for liquid level detection and measuring method

In order to solve the safety hazard caused by the sensor directly contacting the oil when measuring the oil level in the prior art, the invention provides a differential pressure controller for liquidlevel detection. The differential pressure controller comprises a passive detector head used for the detection of a liquid level height, and an air-electric converter used for receiving a signal output by the passive detector head, wherein the passive detector head comprises two liquid inlets separated from each other by high and low liquid levels; the air-electric converter comprises two air pressure sensors and a control unit for receiving the difference between the two air pressure sensors; and the two high and low liquid inlets are respectively connected to the two air pressure sensors for detecting the change data of air pressure of the two high and low liquid inlets. The differential pressure controller reflects the change of the liquid level according to the change of the air pressure, so that the sensor c