The distribution of soluble salt in sediments of in_land lake is close with the hydrochemical feature of lake water, so we can reconstruction the process of hydrochemical evolution of the lake by analyzing the lake's soluble salt deposition. Through coring in the lacuster of Angulinao Lake, testing the eight kinds of ions( K+、Na+、Ca₂+、Mg2+、CO₃₂-、HCO₃-、Cl- and SO₄₂- ) and other related geochemical features, and analyzing the correlation among the ions, the author has drawn the curves of soluble salt distribution and soluble salt indictor. According to the variation of curves of soluble salt, and combining with the varve chronology, the hydrochemical evolution of Angulinao Lake is speculated from the soluble salt distribution of  the core: During 8507~7600 yr B.P., the lake is abundant in Na+ and Cl-, its saltness is high; in 7600~4724 yr B.P., the water is abundant in Na+, Cl- and SO₄₂-, its saltness is very high; in 4724~574 yr B.P., the water is abundant in Na+, CO₃₂- and HCO₃-, its saltness is a little low; since 574 yr B.P., the lake is abundant in Na+ and Cl-, the saltness is low and going up. Comparing with the curves of grain size, the turning points of curves of soluble salt are earlier than curves of grain size, therefore the soluble salt depositon is more sensible to fluctuation of environment , it's a good indictor and should be extended to apply.