Environmental interpretation of geochemical proxies of lake/ocean sediments largely depends on an understanding of where elements are from and of how elements bound to various fractions in the sediments.Fourteen samples from Lake Daihai, Inner Mongolia,located in semiarid zone, were carried out a sequential extraction experiment and analyzed eighteen elements concentration by ICP-AES or A AS in each chemical fractions defined as follows: soluble, exchangeable, bound to carbonate, bound to Fe-Mn-ox-ides, bound to organic matter and residual.Our results indicate that weak chemical weathering was proceeded under climate conditions in the Lake Daihai watershed, resulting that most of the elements deterrained are in residual due to little activation during weathering, except Ca and Sr, by combining with detrital minerals of predominantly plagioclase.Meanwhile, controlled by element affinity and lake water physicochemical conditions, leached both Sr and Ca are in the same fractions with good correlation, whereas other activated elements including Pb, Be, Co, Cut K, Mn, Fe etc are predominantly associated with the fractions of bound to carbonate and/or organic matter.Consequently, element distribution in various chemical fractions provides a useful experimental evidence for selection and interpretation of some geochemical proxies.