Abstract: Objective To summarize the antitumor effect of astaxanthin and its mechanism. Methods We collected and analysed the results from articles related to astaxanthin and tumor. Results astaxanthin have a strong antioxidant effect. and astaxanthin can prevent cancer, inhibit tumor cell proliferation, promote apoptosis, inhibiting metastasis, enhance immunity, regulating cell communication to achieve antitumor effect. Conclusions Astaxanthin has antitumor effect, but the specific mechanism is still unclear. The clinical application of astaxanthin warrants large-scale prospective clinical trials.