Abstract: Under the influence of El Niño/Southern Oscillation (ENSO), the Southern Oscillation Index events, changes in precipitation intensity and duration thereon in both space and time in the Huai River basin, China, are investigated. Different behaviors of precipitation intensity and duration during different ENSO episodes were also analyzed, and significance of these changes was evaluated using Mann–Whitney U test method. Results of this study indicate that: (1) the north Huai River basin is dominated by decreasing precipitation, specifically in the Yi-Shu-Si River basin, and increasing precipitation in the south Huai River basin. Increasing number of annual maximum consecutive dry days, decreasing number of annual maximum consecutive wet days (MCD) and decreasing precipitation amount of annual maximum consecutive wet days (MCP) indicate a drying tendency in the northern parts of the Huai River basin, implying intensifying droughts. However, a wetting tendency is observed in the southeast parts of the Huai River basin as a result of increasing annual total precipitation amount and increasing MCD and MCP; (2) the influence of Eastern Pacific Warming (EPW), Central Pacific Warming (CPW) and Eastern Pacific Cooling (EPC) on heavy precipitation and rainstorms is evident. There is more significant influence of EPC on rainstorms. EPW and CPW cause a higher risk of flooding in the south Huai River basin, whereas EPC causes a higher risk of flooding in the north Huai River basin; (3) longer-lasting precipitation events are observed to be decreasing during the EPC and CPW periods, whereas occurrences of longer-lasting precipitation events are found to be increasing during the EPW period. This study is of practical value in planning and management of agricultural irrigation and water resources and helps understand the influence of ENSO events on precipitation regimes in the Huai River basin, China.