To analyze the mechanism and result of the zinc oxide nanoparticles(ZnO-NPs) injury to zebrafish intestine tissue,this paper has studied the effect of ZnO-NPs on zebrafish intestine tissue structure,antioxidant enzyme activity and apoptotic gene expression.Zebrafish were exposed to the different concentrations of ZnO-NPs(0,0.05,0.1,5,10,25,50 mg/L).The malondialdehyde(MDA),glutathione peroxidase(GSH-PX) and glutathione-s-transferase(GST) in the intestine tissues of zebrafish were measured by colorimetric method at the 4^th,24^th and 96^th hour.The mRNA expressions of Bcl-2, Bax,p53 and MDM2 in intestine tissues were also examined using quantitative real-time PCR assays.The change of anatomical structure in the intestine tissues of zebrafish was observed by Hematoxylin-Eosin(H-E)staining technique after zebrafish were exposed to ZnO-NPs for 7 d,15 d and 30 d.Compared with the control group,the experimental groups were shown as:the MDA content was increased;with a longer exposure time,the activity of GSH-PX and GST first increased and then decreased;the mRNA expression level of genes Bax/Bcl-2 ratio and p53 of experimental groups increased;with a longer exposure time and a higher concentration,the mRNA expression level of gene MDM2 first increased and then decreased.HE staining was observed in the experimental groups,changes in the structure of intestinal tissues were shown as the phenomena that the number of goblet cells and lymphocyte increased,goblet cells swelled,cytoplastic vacuolation,leukomonocyte increased and erosion of villi was observed in zebrafish intestine depending on the time and dose.The results suggest that the oxidative damage of ZnO-NPs to the zebrafish intestine was caused by the increase of oxidative stress,which made enzyme inactivating,induced the expression of cell apoptosis-related genes and caused the damage to histological structure of intestine.