Objective To investigate the dynamic characteristics of intestinal pathological development at different time points in a mouse model of colitis-associated colon cancer. Methods A colitis-cancer model was established in C57BL/6 mice using azoxymethane (AOM) combined with dextran sulfate sodium (DSS). Samples were collected at 7, 10, and 14 weeks post-modeling and the spleen index, colon length, mass, and colon mass per unit length were measured. Histopathological changes in the colon were observed by hematoxylin and eosin and Masson staining. Expression levels of the cancer stem cell marker CD44 and Wnt signaling pathway genes Wnt2b, Lrp5, Axin2, and Znrf3 at different pathological stages were detected by reverse transcription quantitative real time PCR. Cancer-associated fibroblasts (FAP), CD44, the proliferation marker Ki67, and goblet cell MUC2 protein were detected by multiple immunofluorescence histochemistry (mIHC) and immunofluorescence. In addition, colon organoids were isolated from model mice at ten and fourteen weeks and cultured in vitro to observe changes in organoid morphology and marker expression. Results AOM/DSS-induced mice showed reduced, distorted, and branched colon crypt structures with a few collagen fibers at 7 weeks, and varying degrees of colon intraepithelial neoplasia, with an increased proportion of high-grade intraepithelial neoplasia over time and increased collagen fiber staining at ten and fourteen weeks. mRNA levels of CD44 and Wnt2b in the colon were significantly increased (P<0.05) and Axin2 was decreased (P<0.01) in model mice compared with control mice at fourteen week, and levels of Wnt2b, Lrp5, and Znrf3 were increased compared with seven-week mice (P<0.01,P<0.05,P<0.01), and Axin2 was decreased (P<0.01). mIHC staining showed increased expression of FAP and CD44 in the colon in model mice at ten and fourteen weeks, with decreased MUC2 expression. Colon organoids showed cystic dilation, especially at fourteen weeks, with more prominent expression of Ki67 and CD44. Conclusions The AOM/DSS-induced mouse model exhibited chronic colonic inflammation, low-grade intraepithelial neoplasia, and high-grade intraepithelial neoplasia at seven, ten, and fourteen weeks, respectively. The pathological microenvironment was characterized by fibroblast activation and abnormal proliferation of epithelial cells.