The invention discloses an infrasound sensor for leakage detection of a gas pipeline. The infrasound sensor comprises an anti-explosion shell, an infrasound piezoelectric transducer and an infrasound PID conditioning circuit. The anti-explosion shell is mounted on the gas pipeline. The infrasound piezoelectric transducer is arranged in the anti-explosion shell and used for generating pulse charges according to pulse infrasound waves generated during leakage of the gas pipeline. The infrasound PID conditioning circuit is arranged in the anti-explosion shell and connected with the infrasound piezoelectric transducer and is used for converting the pulse charges into simulation signals based on the pipe diameter and pipe pressure of the gas pipeline. According to the infrasound sensor provided in an embodiment of the invention, due to the fact that the final detection result is obtained by converting the pulse charges according to the pipe diameter and pipe pressure of the gas pipeline, it is guaranteed that the infrasound sensor can be widely applied to gas pipelines different in pipe diameter and different in pipe pressure, and meanwhile the false alarm rate of the infrasound sensor is lowered.