Purpose To study thickness of RPE-BM complex in adult Chinese subjects and its correlation with systemic and ocular biometric parameters. Design Population-based longitudinal study. Cross-sectional study. Participants The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6 +/- 9.8 years (range: 50-93 years). Methods A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD OCT) for measurement of the thickness of RPE-BM complex. Use Heidelberg software "Heidelberg Eye Explorer" for segmentation and measurements. Main outcome measure Thickness of RPE-BM complex. Results In total, 3276 people (6530 eyes) were included in the study. In total, 1844 (56.3%) subjects were female. The mean age was 64.3 +/- 9.6 years (range: 50-93 years). The mean refractive error (spherical equivalent) was -0.18 +/- 2.04 diopters (range: -22.0 to +7.50 diopters). Mean thickness of the RPE-BM complex at the foveal center was 25.09 +/- 3.98 mu m (range: 17-37 mu m). In multiple regression analysis, subfoveal thickness of the RPE-BM complex was associated with age (p = 0.039; beta: 0.22; B: 0.10 (95% CI: 0.01, 0.20)) and hypertension history (p = 0.038; beta: 0.23; B: 1.96 (95% CI: 0.12, 3.81)). Conclusion Mean subfoveal thickness of the RPE-BM complex was 25.09 +/- 3.98 mu m in elderly subjects with a mean age of 64.3 years increased with age and hypertension history. The increase in the thickness of RPE-BM complex may play a role in the pathophysiologic features of various age-related ocular conditions.