Using the daily rainfall values to calculate the rainfall erosivity will benefit to the local soil and water conservation activities,improve the sustainable development of tropical agriculture ecosystem.Based on the annual mean rainfall value（1 492.9 mm）from 1959 to 1998 at Menglun climatic station in Xishuangbanna,the erosive rainfall standard referring the values higher than 12.7 mm per 24 h,the daily rainfall values during 1992 to 2006 at the station were analyzed,with the help of formula M=α∑k j=1（Pj）β,which derived from the RUSLE generated from USA for rainfall erosivity calculation,the rainfall erosivity under the unit of half-month was calculated,then the seasonal variation pattern of the rainfall erosivity was generated.The results showed that in terms of annual rainfall amount,45% years were the normal rainfall amount level,the numbers of abundance rainfall years more than deficit rainfall years,total annual rainfall amount increased slightly in the focusing duration comparison with the historical annual mean rainfall records;the annual erosive rainfall amount accounted for over 75% of the total yearly rainfall amounts,the erosive rainfall amounted basically appear in the monsoon season;the annual rainfall erosivity varied from 160.742 to 350.393 MJ·mm·hm-2·a-1,the largest value appeared in 2001;monthly rainfall erosivity changed dramatically from 1.107（in Jan.）to 57.189（in Jul.）MJ·mm·hm-2·h-1,the differences reach over 50 times in different months;the general changing pattern was similar with the rainfall amount variation,and typical seasonal patterns.%研究目标区域降雨侵蚀性的动态特征,有助于制定和实施区域有效水土保持规划,促进区域农业生态系统健康、良好发展。现以西双版纳勐仑气象站1959～1998年平均年降雨量值为参考值,每24h≥12.7mm为侵蚀性降雨标准,分析该站1992～2006年的日雨量值,用修正后的土壤流失通用方程（RUSLE）中计算降雨侵蚀力方程M=α∑kj=1（Pj）β来估算该区域降雨侵蚀力动态变化（MJ.mm.hm-2.h-1）。结果表明：西双版纳勐仑区域在研究时段内,45%的年份为平水年,丰水年份超过枯水年份,总体表现为略微增加现象;同时,侵蚀性降雨量占总降雨量的75%以上,并且集中发生在雨季期间;年降雨侵蚀力值在160.742～350.393MJ.mm.hm-2.a-1,最大侵蚀力出现在2001年;年内不同月份降雨侵蚀力差异明显,雾凉季的1月仅1.107MJ.mm.hm-2.h-1,雨季的7月达到57.189MJ.mm.hm-2.h-1,二者相差50多倍,随后又逐渐降低,表现为明显的季节变化。
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