The Sanjiang Plain is an important production base for commodity grains in China. In recent years, frequent floods and waterlogging have directly affected regional agricultural production and brought serious economic losses. Based on the daily rainfall data in Suibin County from 1957 to 2019 and the occurrence of waterlogging disasters in the past 40 years, the eigenvalues of rainfall, the changing trends and abrupt changes of rainy days of various magnitudes were analyzed using linear trend estimation, Pearson-Ⅲ frequency curve and Mann-Kendall test method. The results of Pearson-Ⅲ frequency curve were combined with the occurrence of waterlogging to analyze the occurrence frequency and causes of waterlogging in the county. The results showed that from 1957 to 2019, the annual rainfall and the maximum daily rainfall in Suibin County increased and there were no abrupt changes. The maximum 3-day rainfall showed a decreasing trend, with abrupt changes in 1981 and 1997. The rainy days of light rain and heavy rain showed a decreasing trend, whereas those of moderate rain and heavy rain showed an increasing trend. The abrupt changes of light rainy days occurred in 2011 and 2016, whereas those of other rainfall magnitudes did not occur. Due to the low and flat topography, heavy summer precipitation, high water level in rivers outside the area, incompetent water conservancy projects, etc., the probability of waterlogging in the county was quite high, which approached 67.5% in the last 40 years, and the incidence of large-scale waterlogging was 30%. Dividing the occurrence rate of large-scale waterlogging by time, the occurrence rate was 50% in the first 10 years, 30% in the middle 10 years, and 20% in the rest 20 years. The significant increase in rice planting area from 1990 to 2019 was the main reason for the decrease in the incidence during this period. The research results can provide a certain reference for flood and waterlogging control for the regional farmlands.