Abstract: Electric power operators are required to regularly maintain and overhaul DC equipment to ensure the safe production and application of the DC transmission system. When maintaining the equipment, it is necessary to detect whether the DC equipment is live and exceeding the safety threshold of electric field strength to ensure the life of the operator and the safety of the equipment. In this paper, measuring the high-voltage DC electric field uses a non-contact method. Developinga self-feedback low-power DC electric field sensor thatbased on the principle of capacitive sensor. Adjusting the range and sensitivity of the sensor by feedback. By optimizing the design of the structural parameters of the DC electric field sensing unit, it is concluded that the number of fan-shaped blade opening lobes of the sensing electrode is n=6 when the amplitude of the induced current signal is the largest at this time. The distance between the shielding electrode and the sensing electrode is d=3mm. The sensing electrode adopts differential signal output, which can suppress the interference of common mode signal. The sensor calibration experiment shows that the range is ±65kV/m, the sensitivity coefficient is 65.6, the accuracy is 0.5kV/m and the measurement error is less than 2%. The sensor has a good consistency and reliability within ±40kV/m. The sensor can not only be used to measure the intensity of high-voltage direct current electric field but also has a broad application prospects in aerospace and meteorological lightning research.