The effects of danofloxacin by oral administration for 20 days at dosage of 20,50 and 100 mg·kg^-1 on the toxicity of Acipenser schrencki were studied. The activity of superoxide dismutase(SOD) ,catalase(CAT),Na⁺，K⁺ATPase，glutathioneStransferase(GSHPX)，glutathione peroxidase(GST) and Maleic Dialdehyde(MDA) content were investigated by kit, so as to appraise security of danofloxacin used in Acipenser schrencki. Meanwhile blood smears were prepared to investi gated the micronucleus and nuclear anomalies rate. The results showed:the SOD activity in erythrocyte remains higher level than that of control group；CAT activity in erythrocyte is higher than control group obviously；The activity of Na⁺, K⁺ATPase in erythrocyte is not significant compared with control group；The GSHPX activity in erythrocyte of 100 mg·kg^-1 is higher than other test groups（P<0.05）；the MDA concentration in erythrocyte remains unchanged；the activity of GST inerythrocyte is not affected by danofloxacin；The erythrocyte micronucleu s remained stable, but nuclear anomalies in test group rose markedly compared with control group. The result showed that the nuclear anomalies are the highest at 10th day, then began to decrease but still is higher obviously than control group. The result showed that danlfloxacin affected SOD，CAT，GSHPX activity, does not changed the Na⁺， K⁺ATPase，GST activity and MDA content. The nuclear anomalies rate of test fish is higher than control group.