Abstract:As the largest freshwater lake in China, revealing the spatial-temporal evolution of the rainfall erosivity and its impacts on sediment into the Poyang Lake is of great significance to scientifically guide the ecological protection and the development of the high-quality development of the ecological civilization in the basin. In this paper, change of the rainfall erosivity in Poyang Lake basin (PYLB) and its effects on suspended sediment load (SSL) into the lake were investigated based on the daily rainfall data of the 63 weather stations within the PLYB and the annual SSL into Poyang lake from its five tributaries from 1961 to 2017, using the non-parameter Mann-Kendall test, Double mass curve and Linear regression method. The results showed that annual average rainfall erosivity of PYLB was 10 034.1 (MJ·mm)/(hm2·h), ranging from 6 738.8 to 12 734.8 (MJ·mm)/(hm2·h). The spatial pattern of the rainfall erosivity showed that low rainfall erosivity mainly distribute in the southwest region and high rainfall erosivity mainly distribute in the northeast region. The rainfall erosivity showed an insignificant increasing trend (P>0.05) during 1961—2017, of which the greatest value was in the 2010s and the smallest in the 1960s. In the same period, the annual average total SSL into the lake was 1 183.3×104 t, showing a significant decreasing trend (P<0.01). The greatest value of the SSL was in the 1970s and the smallest was in the 2000s.The change points of the total SSL into the lake and the SSL of the Ganjiang river, Xinjiang River and Shuishui River were in 1992, and 1999, respectively (P<0.01). Taken the period before the change points of the SSL as the baseline period, the contribution rate of human activity and rainfall erosivity on the total changes of SSL into the lake was -138.1% and 38.1%, respectively during the period after the change point. The contribution rate of human activity and rainfall erosivity on the SSL changes of the Ganjiang river was -125.8% and 25.8%, respectively. The contribution rate of human activity and rainfall erosivity on the SSL changes of the Xinjiang river was -121.3% and 21.3%, respectively. The contribution rate of human activity and rainfall erosivity on the SSL changes of the Xiushui river was -141.4% and 41.4%, respectively. The change of rainfall erosivity was advantageous to increase the SSL into the lake, and human activities, e.g. reservoir construction, soil and water conservation and sand mining were the main driving forces for the decrease of the SSL into the Poyang Lake in the recent 60 years.