Introduction: We aimed to describe the clinical efficacy and safety of tislelizumab, a new (PD-1) inhibitor, in patients with malignant solid tumors.Methods: We searched relevant databases for phase III randomized controlled trials, including patients with solid tumors. The following outcomes are of interest: overall response rate (OS), overall survival (ORR), progression-free survival (PFS), disease control rate (DCR), and treatment-related adverse events (TRAE). We conducted subgroup analyses based on the line of therapy, type of solid tumor, and tislelizumab alone or combined with chemotherapy.Results: Seven phase III RCTs with 3478 were included in the meta-analysis. Pooled analysis demonstrated that tislelizumab significantly improved ORR and DCR with (OR) of 2.59 (95% (CI) = 2.15-3.12, p < 0.00001) and 1.78 (95% CI = 1.43-2.21, p > 0.00001), respectively. Pooled HRs for OS and PFS were 0.71 (95% CI = 0.65-0.78, p > 0.00001) and 0.68 (95% CI = 0.54-0.84, p = 0.0005), respectively.Conclusion: Overall, based on this meta-analysis, the available data strongly supports the utilization of tislelizumab in the treatment of malignant solid tumors.