The changes of visibility in the different kinds of precipitation are studied. The raindrop size distribution data of two weather processes (continuous precipitation and thunderstorm) are analyzed. The results show that the thunderstorm precipitation with low visibility has a wide spectrum of drops, and the continuous precipitation has a narrow spectrum. The particle concentration and visibility are inversely related: the lower particle concentration leads to a rapid improvement in visibility. The concentration of small particles is significantly larger in low visibility, and the small concentration of particles less than 1 mm has the greatest impact on the visibility, followed by 1 to 2 mm particles, indicating that the high concentration of small particles corresponds to the low visibility. The characteristic quantities during precipitation and low visibility periods are relatively high, and after visibility improved, these quantities change suddenly and fluctuate. The calculated visibility is close to the observation at high particle concentration and low visibility.