Objective. This study is aimed at exploring the clinical effect of mechanical traction on lumbar disc herniation (LDH). Methods. Related literatures were retrieved from PubMed, Medline, Embase, CENTRAL, and CNKI databases. Inclusion of literature topic was comparison of mechanical traction and conventional physical therapy for lumbar disc herniation. Jadad scale was used to evaluate the quality of the included RCT studies. The Chi-square test was used for the heterogeneity test, and a random effect model was used with heterogeneity. Subgroup analysis and sensitivity analysis were used to explore the causes of heterogeneity. If there was no heterogeneity, the fixed effect model was used, and funnel plots were used to test publication bias. Results. Visual analog scale (VAS) in the mechanical traction group was lower than that in the conventional physical therapy group ( MD = − 1.39 (95% CI (-1.81, -0.98)), Z = 6.56 , and P < 0.00001 ). There was no heterogeneity among studies ( Ch i 2 = 6.62 , P = 0.25 , and I 2 = 24 %) and no publication bias. Oswestry disability index (ODI) in the mechanical traction group was lower than that in the conventional physical therapy group ( MD = − 6.34 (95% CI (-10.28, -2.39)), Z = 3.15 , and P = 0.002 ). There was no heterogeneity between studies ( Ch i 2 = 6.27 , P = 0.18 , and I 2 = 36 %) and no publication bias. There was no significant difference in Schober test scores between the mechanical traction group and the conventional physical therapy group ( MD = − 0.40 (95% CI (-1.07, 0.28)), Z = 1.16 , and P = 0.25 ). There was no heterogeneity among studies ( Ch i 2 = 1.61 , P = 0.66 , and I 2 = 0 %) and no publication bias. Conclusion. Mechanical traction can effectively relieve lumbar and leg pain and improve ODI in patients with lumbar disc herniation but has no significant effect on spinal motion. The therapeutic effect of mechanical traction was significantly better than that of conventional physical therapy. Lumbar traction can be used in conjunction with other traditional physical therapy.