The temperature field and moisture field of typical siltstone and mudstone interbedded slope in Nanning under extreme climates are analyzed by means of numerical simulation based on soil moisture-heat coupling theory. The moisture-heat coupling behavior,the temperature-moisture filed variations and the impact on slope stability under different combinations of extreme climates are obtained. Results show that dramatic climate change in short time has large impact on the temperature and moisture fields of surface soil; while long-term climate such as arid has great effect on the temperature and moisture fields of deep soil. Rainfall has small influence on temperature field; and during the evaporation after rainfall,the moisture content at a certain depth in the lower part of middle slope increases to some extent,which would disappear in long-term drought. Moreover,the slopes factor of safety increases apparently under the action of evaporation. In particular,in short-term evaporation with high temperature,interbedded slope is more stable than homogeneous slope; while in long term evaporation,homogeneous slope is more stable.