To characterize the palaeoclimatic variations in monsoon margin zone, n-alkane analyses are done on samples collected from one borehole of 15min depth in Dengkou, Inner Mongolia.The results indicate that most samples are dominated by high carbon, primarily nC_(27) and nC_(29), presenting a significant odd-carbon advantage and terrestrial origin.Several samples with a main peak of nC_(25) show the organic origin of partial aquatic plants.However, in the upper part of the borehole, short chain nalkanes are relatively abundant, mainly with nC_(18) as the main peak and without obvious odd-even predominance, reflecting the increased algal biomass.It is found that alternately cold and warm climatic conditions dominated the study area by various distributions of n-alkanes in sediments, in line with lithology and organic carbon isotope variations in this study.