Purpose A relationship between albuminuria and obstructive sleep apnea (OSA) has been documented in previous studies. Nevertheless, the impact of continuous positive airway pressure (CPAP) treatment on albuminuria in subjects with OSA is debated. This meta-analysis was carried out to investigate whether or not CPAP treatment affected urinary albumin-to-creatinine ratio (UACR) in subjects with OSA. Methods A comprehensive literature search was conducted on Web of Science, Embase, and PubMed from January 1990 to December 2020. Information on patients’ characteristics, features of the studies, and UACR of pre- and post-CPAP treatment was collected. For estimation of the pooled effects, standardized mean difference (SMD) was applied. Results This meta-analysis included 6 articles and 211 subjects. The pooled analysis suggested that CPAP therapy exerted a favorable effect on the decrease of UACR in subjects with OSA (SMD = 0.415, 95% CI = 0.026 to 0.804, z = 2.09, p  = 0.037). Subgroup analyses revealed that the CPAP treatment effect was not influenced by sample size, BMI, age, or AHI. Conclusion The present meta-analysis indicated that UACR was significantly reduced by CPAP therapy in subjects with OSA. Further well-designed randomized controlled trials with large sample size are required to confirm the benefits.