Nuclear magnetic resonance (NMR) detection technology is the only known non-excavation direct water detection technology, which has the advantages of comprehensive information, unique interpretation, quantitative results and so on. At present, the main problem faced by nuclear magnetic resonance water detection in the actual detection process is the complex electromagnetic noise interference in the environment, and the signal-to-noise ratio of water detection is difficult to be guaranteed. Through multiple measurements, it is possible to realize multiple superposition of the collected signals, and the signal-to-noise ratio can be improved by \( \sqrt{n} \) times by superposing the signals detected by the instrument n times. The power supply system of the previous MRI water finding instrument adopts the LCC resonance method, which has the problems of small power, low number of signal acquisition times per unit time, and difficult heat dissipation. In this paper, we propose a ZVS-based MRI high-power power supply system with constant resonance, which has a higher duty cycle adjustment range, higher efficiency, and smaller switching loss. Therefore, the time for the power supply to charge the energy storage capacitor can be shortened, and the number of measurements per unit time can be increased, thus improving the signal-to-noise ratio.