With the continuous promotion and application of the second-generation shipborne DC power system, it provides an effective guarantee for the launch of high-energy weapons and high-power and high-frequency weapons. It is important to monitor the voltage of shipborne DC power system to ensure normal operation. Aiming at the problem that the accuracy level of voltage sensor based on voltage divider will decrease with time due to resistor aging caused by complex electromagnetic environment, a self-correction voltage sensor based on resistor voltage divider and electronic switch was introduced. The scheme improves the structure of the voltage divider. A controlled electronic switch is connected in parallel with the resistor, which is at the middle position of the voltage divider, and the microprocessor controls the electronic switch to open and close. According to the principle of voltage divider and time-sharing sampling, the resistance of the high voltage resistor can be evaluated through solving the equations, so as to update the voltage divider ratio to achieve the purpose of self-correction. In this paper, a prototype is developed according to the scheme, and the basic accuracy experiment and self-correction experiment are designed according to its performance indicators. The experimental results show that the range of the voltage sensor prototype meets 0~20 kV, and the measurement accuracy class meets 0.2. The self-correction experiment verifies the effectiveness of the self-correction scheme, which proves that the developed prototype meets the DC medium voltage monitoring requirements.