[Objective]To investigate the efficacy and safety of body constitution on unicompartmental knee arthroplasty. [Methods] The database was searched to September 2023 from CNKI, Wanfang, VIP, China Biomedical Literature Database, PubMed, Embase, Cochrane Library, and Web Of Science. A meta-analysis of the included literature was performed using RevMan 5.4. [Results] A total of 11 articles were included, with sample sizes ranging from 41 to 1000. Among them, 3 were prospective studies and 8 were retrospective studies, all of which were high-quality studies. The meta-analysis results showed that the postoperative revision rate in the obese group was higher than that in the normal group [I2=23%, RR=1.51,95% CI: 1.06-2.14]. The OKS score [I2=89%, MD=-2.99, 95% CI: -5.18-0.81] and joint range of motion [I2=34%, MD=-3.38, 95% CI: -4.32-2.44] in the normal group were slightly better than those in the obese group. There was no statistically significant difference between the obese group and the normal group in VAS score [I2=0, MD=-0.16,95% CI: -0.45-0.13], KSS score [I2=0, MD=-0.32,95% CI: -1.77-1.12], HSS score [I2=0, MD=-0.53,95% CI: -2.26-1.21], and postoperative complications [I2=3%, RR=1.78,95% CI: 0.56-5.70]. [Conclusion] The OKS score and range of motion of the normal group were slightly better than those of the obese group. The rate of postoperative revision in the obese group increased, and patients should be given weight loss guidance before surgery. Overall, unicompartmental knee arthroplasty is beneficial for obese patients.