Abstract: In light of the difficulties in measuring the flow rate of low-productivity producers in oil fields, the heat conduction effect caused by ambient fluid around the detector in the whole measurement cycle was adopted, a downhole flow rate measurement method based on time domain integral of heat transfer was put forward according to multiphase fluid thermodynamic theory. First, intermittent constant power heating was used to provide periodic energy to the detector. Then, an integral method was employed to calculate and analyze the variation of the internal temperature variation law of the detector with the external fluid flow during heating and cooling. The theoretical analysis and experimental study showed that the time domain integral area had an excellent correlation with the flow rate, and had high resolution under low flow rate condition. The problem that traditional turbine flowmeters lose their capability of detection as their turbines couldn’t be activated under low flow rate was solved with this method. The downhole flow rate measurement method based on the time domain integral of heat conduction has promoted the development of oil-water two-phase flow detection technology. It has provided a new technical means for flow rate measurement of low-productivity producers.