Objective: To observe the changes of peripapillary vascular density (VD) and its correlation with retinal nerve fiber layer (RNFL) thickness in patients with unilateral retinal vein occlusion (RVO) by optical coherence tomography angiography(OCTA). Methods: Prospective case-control study. Thirty-two patients (32 eyes) with RVO diagnosed at the Eye Hospital of China Academy of Chinese Medical Sciences from September 2020 to June 2021 were selected. Another 32 outpatients (32 eyes) with normal ocular examination were selected as the normal control group.Optic disc blood flow imaging was performed in all subjects using the OCTA to measure peripapillary RNFL thickness, peripapillary vessel density, optic disc area, and disc rim area.The correlation between peripapillary vascular density and RNFL, optic disc area and disc rim area in eyes with unilateral RVO was analyzed. Results: Compared with the normal control group, the prevalence of hypertension was higher in the unilateral RVO group, and the difference was statistically significant (P<0.05). Compared with the normal control group, the overall, inferior and temporal RNFL thickness around the optic disc was thinner in patients with unilateral RVO, and the difference was statistically significant (P<005). Compared with the normal control group, the overall VD, internal ring, external ring and inferior VD around the optic disc were slightly decreased in patients with unilateral RVO, and the differences were statistically significant (P<0.05). The results of Pearson correlation analysis indicated that RNFL thickness was positively correlated with peripapillary global VD (r=0.648, P<0.001), RNFL thickness was positively correlated with intrapapillary ring VD (r=0.427, P=0.015), and RNFL thickness was positively correlated with peripapillary VD (r=0.666, P<0.001). Conclusion: The results showed that the RNFL thickness around the optic disc was thinner in patients with unilateral RVO, especially in the inferior and temporal area, and the full area VD around the optic disc was decreased, especially in the internal ring, external ring and inferior area. In patients with unilateral RVO, peripapillary RNFL was positively correlated with peripapillary global, internal ring and external ring VD.