Abstract: Objective To determine the genotoxicity of non-volatile organic compounds(NOCs)in raw and tap water of eset lake at Wuhan.Methods The NOCs in water were concentrated on XAD-2 resin and the genotoxicity of such compounds were examined by using mouse micronucleus text.Results The NOCs in raw and tap water could increases frequency of micronucleus in mouse bone marrow cells obviously and at the same time the dose response relation of them could be observed.Frequency of micronucleus caused by organic compounds is high in aver age and high period than that in low flow period.Conclusion The NOCs in water of various hydrographic could cause the genotoxicity for mouse bone marrow cells.