The invention relates to a bored pile concrete interface monitoring device which is designed through an electrical impedance physical property testing method for media such as concrete, slurry and water in the bored pile underwater concrete pouring process and sensitivity test analysis and through researches on the testing method and instrument for an underwater electrical impedance testing probe and underwater concrete pouring elevation positioning. The bored pile concrete interface monitoring device comprises a ground host, a probe electronic cavity, a push rod arranged on the top of the probe electronic cavity, an insulation rod arranged at the bottom of the probe electronic cavity, a first electrode, a second electrode, a resistance value measuring module and an analog-digital converter, wherein the first electrode and the second electrode are fixedly connected to the insulation rod in a sleeving mode, and the resistance value measuring module and the analog-digital converter are arranged in the probe electronic cavity. According to the key technological principle, in the pouring process of a pouring hole, the electrical impedance of water and slurry is obviously different form that of the concrete, and the positioning of the concrete pouring interface (or depth) is achieved by measuring the difference.