In order to overcome the limitations of the existing human body detection technology, a human body drop detection method based on capacitance detection is proposed. Firstly, basic principle of human detection method based on capacitance detection is studied. Secondly, theoretical model of measurement circuit is proposed, and feasibility of the model is verified by simulation. Finally, the actual measurement circuit suitable for field applications is designed and an experimental platform to simulate a closed pipeline environment is build. Experiments have shown that this measurement method can quickly and effectively detect the human body when the human body falls into a closed pipe.