Objective To observe the inhibitory effects of construction of complement factor (CFB)small interference RNA (siRNA) on choroidal neovascularization（CNV）induced by photocoagulation in rats.Methods We constructed an expression vector of CFBsiRNA by cutting CFBsiRNA and plasmid pRNATU61/Neo. Experimental CNV was induced by photocoagulation in 42 Brown Norway rats. After the model was set up, the rats were randomly divided into tail intravenous injection, vitreous injection, subretinal injection, and control group; each group except the control one had a corresponding blank plasmid control group. CFBsiRNA was injected 1, 3, and 5 days respectively after photocoagulation in the injection groups; the dosage was 50, 20, and 10 mu;g in tail intravenous injection, vitreous injection, and subretinal injection group respectively, while no injection was give to the control group after photocoagulation. Before and 14 days after photocoagulation, fundus fluorescein angiograoph (FFA) was performed and CNV development was judged by the leakage; the expression of vascular endothelial growth factor (VEGF) and factor Ⅷ were detected by immunohistochemistry. Results The leakage of fluorescein was obvious lower in tail intravenous injection group than that in the control group (chi;2=15.1620,Plt;0.05). The expression of VEGF and factor VIII in tail intravenous injection group at different time points after photocoagulation didnprime;tdiffer much (F=20.35,18.33; Pgt;0.05); while was apparently lower than that in the other groups at different time points (F=77.96,55.68; Plt;0.05).All of the groups, except tail intravenous injection group, had higher expression of VEGF and factor VIII 14 days after photocoagulation compared with that 7 days after photocoagulation (F=60.89, 61.12; Plt;0.05).Conclusions Constructed CFBsiRNA can inhibite CNV by downregulating the expression of VEGF and factor Ⅷ.