Objective To investigate the expression and signification of Transforming growth factor-?1 and its typeⅠReceptor in choroidal neovascularization(CNV) induced with krypton laser on Brown Norway rat. Design Experimental study. Participants Five groups of 30 BN rats. Methods The rats were photocoagulated with krypton laser in single eye to induce CNV. 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks after photocoagulation, the retina was processed respectively for immunohistochemistry of FⅧR:Ag, TGF-?1 and T?RⅠ, in situ hybridization of TGF-?1mRNA. Main Outcome Measures FⅧR:Ag, TGF-?1, TGF-?1mRNA and T?RⅠ. Results FⅧR:Ag positive staining cells formed vessels in the lesion 1 week after photocoagulation. TGF-?1mRNA expressed in the ganglion cells, RPE in normal BN retina, TGF-?1 and T?RⅠexpressed in the ganglion cells, inner nuclear layer, RPE in normal BN retina, and they all expressed in the lesions after photocoagulation. From 3 days to 4 weeks, the expression density of FⅧR:Ag in the lesions increased (P