Stream water samples under the Korean pine broad-leaved forest, spruce-fir forest, and larch plantation in Liangshui Nature Reserve of Xiaoxing' an Mountains were collected monthly from March to October 2006 to study the dynamic changes of their hydrochemical characteristics. The results indicated that the content of major cations in the streams was in the sequence of Ca2+ > Na+ > K+ > Mg2+, and that of anions was HCO3(-) > SO4(2-) > NO3(-) > Cl(-). The average content of Na+, Ca2+, Mg2+, Fe2+ and Fe3+ was in the order of spruce-fir forest > larch plantation > Korean pine broad-leaved forest, while that of K+ was in the order of larch plantation > spruce-fir forest > Korean pine broad-leaved forest. The average monthly content of anions in stream water was the highest under larch plantation.