Objective：To explore the expression of CD146 in polyethylene glycol（PEG）-induced choroidal neovascularization（CNV） in a mouse model and its significance. Methods：Sixty 8-week-old male C57BL/6J mice were randomly and equally divided into 5-day group，10-day group，and 15-day group using a random number table. The left eye was set as a normal control eye，while the right eye was set as an experimental eye. The CNV model was established by subretinal injection of PEG. After model establishment，the eyeballs of mice were collected in each group. The sections of the retina were stained with hematoxylin-eosin（HE） to evaluate the CNV model. Thickness of the outer nuclear layer（ONL） in HE-stained sections of the retina was compared between the three groups to evaluate the retinal toxicity of PEG. The mRNA levels of CD146，vascular endothelial growth factor（VEGF），and vascular endothelial growth factor receptor 2（VEGFR2） in the neuroretina and RPE/choroid complex were determined by RT-PCR. Im－munohistochemical staining was used to measure the expression of CD146，VEGF，and VEGFR2 in the eyes of mice. Results：Both HE staining and thickness of the ONL confirmed that model establishment by subretinal injection of PEG was successful and reliable. The development of CNV was observed at 5 and 10 days after subretinal injection. The mRNA expression of CD146，VEGF，and VEGFR2 in the neuroretina and choroid was significantly higher in the experiment group than in the control group（F=30.412，P=0.000；F=84.974，P=0.000；F=117.423，P=0.000；F=918.786，P=0.000；F=319.110，P=0.000；F=113.896，P=0.000）. The Pearson correlation analysis showed that the expression of CD146 was positively correlated with the expression of VEGF and VEGFR2 in the RPE/choroid complex after subretinal injection of PEG（r=0.940，P=0.000；r=0.940，P=0.000；r=0.769，P=0.045；r=0.910，P=0.003；r=0.910，P=0.003；r=0.777，P=0.042）. The results of immunohistochemical staining showed that at 10 days after model establishment，the model group had significantly higher expression of CD146 and VEGFR2 in the ganglion cell layer，inner nuclear layer，outer plexi－form layer，and ONL than the normal control group（P=0.000，P=0.000，P=0.000）. Conclusion：The expression of CD146 is up-reg－ulated with the development of CNV and positively correlated with the expression of VEGF and VEGFR2. Therefore，CD146 may play a crucial role in the development of CNV.