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The shape, diameter and fall velocity are the key physical characteristics of raindrops. Thus it is imperative that we begin to focus on the direction of physical characteristics of raindrops. In order to obtain physical properties of raindrops, light field and imaging system were designed based on the particle imaging transient visual measurement technology. The software for image identification, extraction and measurement were investigated, and a natural precipitation imaging measurement system based on a charge coupled device sensor was established. The result of the experiment on steel ball showed that the measurement technology had small relative error. By the field experiment, we found that mediumsized particles were the predominant contributor in the single rainfall, with the diameter of 2.00mm and average fall velocity of 3.52m/s. Mathematic model was developed to calibrate fall velocity and diameter by using linear regression, and the prediction accuracy and precision were reliable. In conclusion, characteristics of raindrops can be measured precisely by the proposed technology, which is a novel method for observing rainfall properties and further researching soil erosion.