Development and establishment of the methods for screening chemicals and evaluating aquatic environment are important scientific issues in environmental research. Aquatic ecotoxicological principles and comprehensive biomarkers of aquatic organisms are the most effective ways to evaluate the potential effects of chemical pollutants to aquatic ecosystem and water quality. In this study PAHs and domestic detergents were selected to explore the method for using aquatic ecotoxicology principles and biomarkers to evaluate chemicals, and to evaluate the potential hazard of extensively existent substance in the environment. The main results are shown as below: 1. After gold-lined sea bream was short time exposed to benzo(a)pyrene (B(a)P), while its behavior was normal, its gill ATPase activity decreased, and liver GST activity and DNA adduct level increased. The result, on one hand suggested the early effect of B(a)P on fish, on the other hand indicated comprehensive biomarkers could reflect the toxicities of B(a)P including potential carcinogenicity. 2. In water bodies with different water quality, mussel gill DNA adduct levels showed a correlation with concentrations of PAHs and were very close to the status of water quality. This result made clear that DNA adduct, as a biomarker, not only reflected the status of pollutions in the environment objectively, but also implied possible influence on organism. 3. The domestic detergents had acute toxicity on Daphnia magna, HB and fish fries, in vitro and in vivo inhibition on ATPase of fish, and significant effect on the reproduction of zooplankton at non-lethal concentration. The toxicities exerted by domestic detergents on fish and daphnia are very obviously. 4. When crucian carp was exposed to detergents with very lower concentration for two weeks, each biomarker reflected the effect of detergents on it. This result showed that comprehensive biomarkers could be used to detect the early influence of chemicals on organism. It is also further proved that attention should be given to potential hazards of domestic detergents on fish and zooplankton.