To explore the cave drip water and the variation characteristics of its corresponding oxygen isotopes in modern deposits and their significance to the climatic environment,the atmospheric precipitation outside the Naduo cave in Guizhou,cave pool water,six drip points and their corresponding modern deposits oxygen stable isotopes have been monitored for the past 2years.The results show that thedelta~(18) O in atmospheric precipitation,drip water,and deposits of Naduo cave are generally lower than those in most other southern regions.However,the seasonal variation ofdelta~(18) O from all three sources is significant.For example,thedelta~(18) O in atmospheric precipitation outside Naduo cave and in cave pool water both have seasonal characteristics that are higher in the dry season and lower in the wet season,and can basically reflect the climate change in the area where the cave is located.Though thedelta~(18) O in deposits and drip water have similar seasonal variation,they show a very different pattern from thedelta~(18) O in the atmospheric precipitation.This may be the result of the combination of regional topography,karst surface zone regulation,and atmospheric circulation.