Objective To systematically review the efficacy and safety of CDK4/6 inhibitors in combination with endocrine therapy for HR+/HER2‒ breast cancer. Methods The PubMed, Cochrane Library, Web of Science, WanFang Data, CNKI, American Society of Clinical Oncology (ASCO), European Society of Medical Oncology (ESMO) and San Antonio Breast Cancer Symposium (SABCS) databases were electronically searched to collect randomized controlled trials on CDK4/6 inhibitors in combination with endocrine therapy for HR+/HER2‒ breast cancer from inception to July 5, 2023. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies. Meta-analysis was then performed using RevMan 5.4 software and Stata 14.0 software. Results A total of 8 studies involving 4 580 patients were included. The results of meta-analysis showed that overall survival and progression-free survival were significantly longer in the combination therapy group than those in the endocrine therapy alone group (HR=0.80, 95%CI 0.73 to 0.89, P<0.05; HR=0.54, 95%CI 0.50 to 0.59, P<0.05). The results also showed that patients in the combination therapy group also had significantly higher rates of objective remission and clinical benefit than those in the endocrine therapy group alone (RR=1.47, 95%CI 1.34 to 1.62, P<0.05; RR=1.20, 95%CI 1.11 to 1.30, P<0.05). In addition, the combination treatment group also increased the incidence of haematological toxicity such as neutropenia and leucopenia, but the differences in the incidence of nausea, diarrhoea and headache were not statistically significant between the two groups. Conclusion The combination of CDK4/6 inhibitors with endocrine therapy for HR+/HER2‒ breast cancer patients improve overall survival, progression-free survival, clinical benefit rate and objective remission rate, with significant long-term and near-term efficacy; however, this regimen increased the incidence of several adverse effects, and clinical use should be considered when considering the occurrence of serious adverse effects.