Abstract: Objective　To explore the curative effect of ursodeoxycholi acid on retinopathy of prematurity (ROP) caused by high concentration of oxygen in newborn rats. Methods The model of ROP was established. Neonatal rats were divided into normal control group, ROP model group, low dose ursodeoxycholi acid treatment group (10mg/kg) and high dose ursodeoxycholi acid treatment group (40mg/kg). Rats were sacrificed at days 17. The new retinal vessels were observed and counted under fluorescence microscope. Results The new retinal vessels in ROP rats were hyperplastic, twisted and unevenly distributed. There was significant difference in the number of new retinal vessels among different groups (P=0.000). The number of new retinal vessels of rats in ROP group, low-dose group and high-dose group was significantly more than that in control group (P=0.000). The number of new retinal vessels in low-dose group and high-dose group was significantly less than that in ROP group (P<0.05). The number of new retinal vessels in high-dose group was less than that in low-dose group (P>0.05). Conclusions Ursodeoxycholi acid could inhibit the angiogenesis of retina and could have curative effect on ROP.