This article uses hourly precipitation data from 87 national basic meteorological stations in Jiangxi Province from 2001 to 2020 and 736 regional meteorological monitoring stations in Jiangxi Province from 2010 to 2020, and uses climate statistical methods to analyze the daily variation characteristics of precipitation during the main flood season (April July) in Jiangxi. The results indicate that: 1) The overall daily variation of precipitation and precipitation frequency during the main flood season in Jiangxi Province is characterized by a bimodal structure, with the main peak of precipitation occurring around 18:00 and the main peak of precipitation frequency around 20:00. 2) The diurnal variation of precipitation has regional differences. The main peak time of precipitation and intensity in the northern Jiangxi region along the Yangtze River and other northern Jiangxi regions mostly occurs from morning to morning, while the precipitation, frequency, and intensity in central and southern Jiangxi mostly occur from afternoon to evening. 3) There are also monthly differences in the daily variation of precipitation, and it is related to the duration of precipitation events. The peak precipitation of ≥ 6h continuous precipitation events is prone to occur from morning to morning, which is more prominent in June, while the peak precipitation of ≤ 4h precipitation events is prone to occur from afternoon to evening, which is most obvious in July. 4) General precipitation (<20mm . h-1), short-term strong precipitation (≥ 20mm . h-1), and hourly extreme precipitation with a 5-year return period have a bimodal feature. The main peak of general precipitation is at 16:00, while short-term strong precipitation and hourly extreme precipitation with a 5-year return period are at 18:00. 5) There are differences in daily precipitation changes between river valleys and plain stations with similar latitudes. The precipitation at the selected stations in the Poyang Lake Plain is mostly lower during the day than in the Xinjiang and Changjiang river valleys; There are also differences in the daily variation of precipitation at different altitudes of stations. The precipitation at stations with higher altitudes in the mountainous areas of Gannan is greater than that at stations with lower altitudes at all times of the day, with the maximum difference occurring from 17:00 to 18:00