Abstract: In this paper,the drought/flood indexes for the divisions in the Huanghe River Basin during the last 100 years (1891-1990) are analysed to reveal abrupt climatic change using the Mann-Kendall Test.It is found that there existed abrupt climatic change of drought/flood in 1910 and 1912 over the middle and lower reaches respectively,but no such obvious abrupt climatic change is found over the upper reaches.These facts show that there existed abrupt climatic changes of drought/flood for most parts of the basin during the 1910s,which were jumps from flood to drought phases.Meanwhile, it is should be pointed out that the jump was not non-local event in the basin.In addition,the possible reasons causing the jumps are discussed.By analysing the South Oscillation Index and the air temperature of the Northern Hemisphere using the same test, one can see that their abrupt changes occurred earlier than that of the drought/flood,indicating that these may be improtant background conditions for the event of abrupt climatic change of drought/flood.