Objective To investigate the effects of Akkermansia muciniphila (AKK) on azomethane-oxide (AOM)/glucan sodium sulfate (DSS)-induced inflammatory colorectal cancer mouse model and intestinal stem cells. Methods AOM/DSS-induced mouse models of inflammatory-associated colorectal cancer were randomly divided into three groups, namely, model, AKK and aspirin groups, based on different administration of drugs by gavage. The tumor number, size, distribution, and burden were observed 10 weeks after intervention. Immunohistochemical method was used to analyze the expressions of Ki67 and Lgr5 proteins, which are utilized to characterize tumor malignancy and stem cells. The mRNA expressions of Lgr5, CD133, Nanog, and ALDH1 were detected by qRT-PCR. Results Compared with those of the model group, the tumor number, size, and burden of the AKK group were significantly reduced (P < 0.01). The expressions of Ki67 and Lgr5 in the AKK group of tumor tissues were significantly decreased (P < 0.05), and the mRNA expressions of CD133, Nanog and ALDH1 were significantly down-regulated. Conclusion AKK is effective against AOM/DSS-induced colitis-associated colorectal cancer in mice, and its mechanism of action may be closely related to colorectal stem cell activity.