Phase and frequency are two important parameters of the industrial-frequency AC signal in in the high-voltage electric power system. Phase-detecting experiments are more frequently and importantly required at the scenes of completion and commissioning. As the so-called phasing, the detecting experiment mainly includes detecting the phase and phase sequence, which means to measure the phase difference between the two power line. Meanwhile, in the monitor of power system, factors such as power factor , active power P, wattless power Q and electricity consumption are commonly needed to be monitored, and these factors are directly related to the volume of the AC current and voltage phase difference angle . The paper proposed an untouched phase-detecting sensor for the high-voltage power lines. The sensor is developed in the full hardware method based on digital-to-analog circuit and moreover equipped with wireless communication interfaces. Not only facilitating remote transmission of the phase information, it also can be widely applied in the power industry such as measurement of high-voltage wire phase, phase detecting, voltage measurement and electricity detection