The feed detection device plays an important role in ensuring gas overrun locking function in underground coal mine. How to effectively solve the feed detection misjudgment caused by external interference is still a difficult problem at present. To solve the above problems, a feed detection sensor based on the second order generalized integrator（ＳＯＧＩ） digital processing model is designed in this paper. Through the hardware filter amplification and software filter processing analysis of the weak signal induced by induction coupling, the phase angle difference between two live wires in three-phase power is obtained, and the phase angle difference is judged whether it is within the set threshold range, so as to detect and judge whether the feed state is there or not. The actual operation of the site shows that: after the improved feed detection sensor is used in places with strong interference signals, compared with the original sensor, the feed detection accuracy has been greatly improved, which can meet the needs of digitalization and intellectualization on site.