Abstract: Daily precipitation data of 19 meteorological stations on Hainan Island from 1951 to 2020 were analyzed to identify drought–flood abrupt alternation events using the Long-cycle Drought–Flood Abrupt Alternation Index (LDFAI). The Mann-Kendall test, wavelet analysis, R/S analysis, and multiple linear regression were used to study the temporal and spatial distribution characteristics and the driving forces behind these events. The results showed the following: 1) From 1951 to 2020, there was a significant decrease in LDFAI in Ledong and Baoting, while the other 17 meteorological stations showed no significant change. The years of LDFAI mutations across Hainan Island were scattered, with potential mutations occurring in Danzhou, Wenchang, and Qiongzhong in 2006; Sanya, Baoting, and Lingshui in 2019; and Baisha, Ledong, Qionghai, and Wanning in 1958, 1976, 1992, and 2017, respectively. 2) Hainan Island experienced 27 abrupt drought–flood alternation events from 1951 to 2020. The periodic oscillations of the LDFAI sequence from May to October at various stations were more pronounced at scales of 4 a, 15–20 a, and 40 a, with the 20-a cycle being the most active, persistent, and significant. The future trends of the LDFAI in Wanning and Lingshui were anticipated to be opposite to that observed from 1951 to 2020. 3) Precipitation emerged as the main influencing factor for abrupt drought–flood alternation events on Hainan Island. Among the teleconnection indices, Niño3.4 had the most significant impact on these events. The coupling coefficients of the meteorological factors (M) and teleconnection factors (T) were the highest in Ledong. Compared with the coupling of a single teleconnection factor, the coupling of M and T had the greatest impact on Danzhou. The influence of teleconnection factors on the occurrence of drought–flood abrupt alternation events on Hainan Island shows an increasing trend, further proving that abnormal atmospheric circulation patterns are increasing the frequency of these events.