Background: Interleukin-33 (IL-33) has recently been implicated in tumor development. Methods: Data was obtained from PubMed, EMBASE, Clinical trial, Cochrane Library, Web of Science, CNKI and Wanfang databases. After quality assessment and data extraction, a meta-analysis was performed using Review Manager 5.2 software. Results: There were eight documents included in this meta-analysis. The results showed IL33 levels to be higher in tumor patients than that in health people, but no correlations tumor stage, metastasis and survival time of tumor patients were evident. Conclusion: IL33 may be useful as an alarm factor in tumor detection and prognosis.