By analyzing the raindrop spectrum data of five different precipitation intensities at Suining national basic meteorological station, this paper explores the method of calculating hourly rainfall kinetic energy from the raindrop spectrum data of Dsg4 precipitation weather phenomenon instrument. The results show that the rainfall kinetic energy varies greatly under various rainfall intensities. The greater the rainfall is, the greater the rainfall kinetic energy. The rainfall kinetic energy is positively correlated with the number of hourly raindrops, the average velocity of raindrops and the average diameter of raindrops. Using the research results of this paper, combined with the rainfall kinetic energy threshold of soil and water loss, the soil and water conservation and its early warning ability along the Fujiang River basin can be improved.