The utility model discloses a measure non - oil pumping motor -pumped well liquid measure device on line based on the differential pressure method, including first screw pump well and second screw pump well, first screw pump well and the punishment of second screw pump well do not are provided with first differential pressure measuring device and second differential pressure measuring device, and first differential pressure measuring device and second differential pressure measuring device are connected to perception measuring equipment, and perception measuring equipment is connected to the data acquisition device that sets up through communication module in the RTU switch board, and the data acquisition device is connected to customer end to host computer, host computer through the server with the data transfer who collects through DTU equipment. The utility model also provides a measure non - oil pumping motor -pumped well liquid measure method on line based on the differential pressure method, contain following step: the step 1, by first differential pressure measuring device and the required creation data of second differential pressure measuring device collection, acquisition parameter includes pressure differential, hydrostatic pressure, pressure ratio isoparametric, the step 2, the data of collection are uploaded to the host computer through CDMA and GPRS wireless communication unit through the RTU switch board, step 3, host computer are set up heterogeneous class of flow at the well head and are calculated the model, but calculate the efflux coefficient coefficient of expansion of heterogeneous fluid.