Different typical water samples were collected from July 22 to July 28 in 2005 in Lijiang Basin of the Hengduan Mountainous Region for chemical characteristics study.Principal component analysis(PCA) and correlation analysis were used for data analysis

the results showed that the dominant cations were Ca2+ and Mg2+

whereas SO4-2 were major anions.The analytical results suggested that the orders of water concentration

from high to low

were the glacial lake water

melt water runoff

lake water

surface runoff and groundwater.PCA results showed the lithological characters definitively influenced the ion content of water in the Lijiang basin

which also were effected by human activities.Correlation analysis showed that the concentration of Na+

K+

Mg2+

Ca2+ highly correlated with the lithology

whereas Cl-

and NO-3 concentration had a positive correlation with human activities.High correlation between Ca2+ and Mg2+ suggested their strong common source.Further analysis shows that H2SO4 participating in and accelerating the carbonate and sulfate mineral dissolution related to the above.Cl-and NO-3 with strong correlation were closely related to human activities indicating Cl-and NO-3 have similar sources of which most come from human activities.