Objective: To systematically evaluate the efficacy of probiotic intervention in early life for preventing allergic diseases in children. Methods: Databases including Wanfang, CNKI, CBM, Cochrane Library, PubMed, Web of Science, and Embase were searched for randomized controlled trials (RCTs) on the efficacy of probiotic intervention in early life for preventing allergic diseases. Reviewers screened the literature, extracted data, and evaluated the risk of bias in the included studies. The risk of bias for the included studies was assessed in accordance with the guidelines for bias assessment provided in the Cochrane Handbook. Meta-analysis was performed using Stata 11.0. Results: A total of 44 literatures were ultimately included, with 28 on eczema, 21 on asthma, 16 on wheezing, 16 on food allergy, 9 on allergic rhinitis, and 6 on allergic rhinoconjunctivitis. The results showed that probiotic intervention in early life had a significant effect on preventing eczema (RR = 0.79, 95% CI: 0.68 - 0.91, P = 0.001). However, it had no significant effect on preventing asthma (RR = 0.93, 95% CI: 0.81 - 1.07, P = 0.335), wheezing (RR = 0.92, 95% CI: 0.80 - 1.07, P = 0.283), food allergy (RR = 0.79, 95% CI: 0.58 - 1.08, P = 0.139), allergic rhinitis (RR = 1.03, 95% CI: 0.75 - 1.41, P = 0.865), and allergic rhinoconjunctivitis (RR = 0.88, 95% CI: 0.62 - 1.25, P = 0.461). Conclusion: Probiotic intervention in early life has a preventive effect on eczema in children, but no significant effect on preventing asthma, wheezing, allergic rhinitis, and allergic rhinoconjunctivitis. Further research is needed on its mechanism.