Abstract: The paper deals with contents of As、Hg、Cd、Cu、Pb、Se、Zn in Cyprinus carpio L., Corleus heterodon (Bleeker), Parasilurus sp., and L.longirostris Gunther from the reaches of the Three Gorge Reservoir area. The ration matching analysis indicates that there is no correlation between samples or elements.Bioconcentration factors of mercury for C. carpio L., C. heterodon (Bleeker),Silurus sp., and L. longirostris Gunther are 8.0×103, 1.5×104, 3.3×104 and 8.4 ×103 respectively. This shows that contents of mercury in fish are related to trophic level of their food chain or web, the higher the trophic level of fish, the greater the bioconcentration factors. Ration values of Hg contents in muscle to that in liver or kidney and spleen are 6;2:1 for C. carpio L., Silurus sp., and L.longirostris Gunther,but 1:1:2.5 for C. heterondon (Bleeker). Organic mercury contonts in these organs are 84%-92%. There are good correlations between organic and inorganic mercury contents in fish:Hg-o=-0.001094+0.9101Hgt p0.01 The relationships between mercury contents in carp muscle (C) and body length(L) or body weight (W) have the forms: LnC＝A+BLnL LnC＝A'+B'LnW The authors point out that because of mercury pollution in the Three Gorge Reservoir area, mercury contents in carp are greater than background values of mercury in carp from the Changjing River water system.