Ulcerative colitis (UC) is among the common autoimmune disease worldwide. Circular RNAs (CircRNAs) are members of the noncoding RNA family (NcRNAs), in addition to its role in numerous biological processes, they are also linked to a vast range of diseases, including UC. Although previous studies looking at many circRNAs, we are still unclear about the physiological and pathological roles of the circRNAs-associated competing endogenous RNA (ceRNA) network in UC. Based on this, we constructed a circRNA–miRNA–mRNA network based on the ceRNA theory by analyzing from the National Center for Biotechnology Information Gene Expression Omnibus (NCBI-GEO) database. Genes with higher degrees than others in the ceRNA network were selected as central nodes in constructing the corresponding core subnetworks. In order to fully comprehend the biological function of the ceRNA network, we entered all differentially expressed mRNAs (DEmRNAs) which from the ceRNA network into the Database for Annotation and Integrated Discovery (DAVID) for GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses and the STRING for PPI: protein-protein interaction (PPI) network analysis, genes with the degree value > 5 were defined as the hub genes in the regulatory network. In a nutshell, the ceRNA network was composed of 403 circRNA nodes, 5 miRNA nodes, 138 mRNA nodes and 559 edges. 3 core ceRNA subnetworks centered on hsa-miR-342-3p, hsa-miR-199a-5p and hsa-miR-142-3p were reconstructed. The results elucidated that enrichment of 167 GO categories and 14 KEGG pathway terms. The core PPI network was made up of 15 core targets, of which CD44, HIF1A and MMP2 were the most significant core targets. Overall, this study offered a comprehensive and detailed analysis of the fundamental roles that the ceRNA network played in UC, the hub nodes derived from this research may also serve as diagnostic markers and therapeutic targets.