Abstract: To study the effect of DEHP Di-(2-ethylhexyl) phthalate on the nonspecific immune function and genetic toxicity in Cyprinus carpio, four experimental concentrations of 5, 20, 80 and 160 mg/L of DEHP were treated to the C. Carpio for 20 days, H2O and Tween-80 were used as the controls respectively. The results showed that, when compared with the two controls, all indexes showed no significantly difference except the total nuclear abnormal rate in erythrocytes which significantly increased in the Tween-80 group. Phagocytic activity and index (PI) of leucocytes, antibacterial activity and lysozyme activity of serum in the 80, 160 mg/L of DEHP groups were significantly lower than those in the two controls, and also phagocytic activity and index (PI) of leucocytes in 20 mg/L group decreased remarkably (P0.05 or P0.01) when compared with the water control group. When compared with the tween-80 group, the C3 content in serum of the 160 mg/L group decreased significantly. However, the C3 content in the groups of 5, 20 and 80 mg/L, and the C4 content in the groups of 5, 20, 80 and 160 mg/L showed no significantly differences. When compared with the water control group, the C3 content in the groups of 20, 80 and 160 mg/L, and the C4 content in the group of 160 mg/L decreased remarkably (P0.05 or P0.01). Micronuclei rate of erythrocytes in the group of 160 mg/L was significantly higher than that in the group of tween-80, and micronuclei rate of erythrocytes in the group of 80 and 160 mg/L was significantly higher than that in the water control group. In the range of the DEHP concentration, the rate of nuclear abnormalities and total nuclear abnormalities of erythrocytes and the DPC coefficient of hepatocyte all increased significantly when compared with the two control groups.The immune and genetic toxicity on carp can be caused by a certain concentration of DEHP.