〔Abstract〕 Objective To the effects and potential mechanisms of ST3GAL5 on biological behaviors of Bladder Urothelial Carcinoma(BLCA). Methods Differentially expressed genes related to bladder cancer were identified using microarray analysis. Suitable bladder cancer cell lines were then screened. In vitro experimental measurements, including CCK8, EdU, colony formation assays, transwell migration, flow cytometry apoptosis experiments, scratch assay, were used to evaluate the effects of ST3GAL5 on biological behaviors of BLCA. ST3GAL5 gene Kyoto Encyclopedia of Genes and Genomes(KEGG), gene set enrichment analysis(GSEA) were analyzed using The Cancer Genome Atlas(TCGA) database.Finally, Western blot technology was used to verify the classical proliferation and metastasis related pathway factors. Results The combination of bioinformatics analyses and experimental measurements demonstrate that ST3GAL5 expression is aberrantly down-regulated in human cell lines of BLCA. Through Cancer Cell Line Encyclopedia(CCLE) database, HT-1376 cell lines were successfully screened for vitro test. Upregulation of ST3GAL5 was found to suppress the malignant biological behaviour of bladder cancer. GSEA enrichment analyses exhibited that ST3GAL5 and its co-expressed genes inhibited cell proliferation, invasion and metastasis of bladder urothelial carcinoma by activation of the PPAR pathway and inhibition of the PI3K/AKT pathway. The results of Western blot experiments verified that the key proteins of the PPAR signaling pathway showed a significant increase and the key proteins of the PI3K/AKT signaling pathway showed a significant decrease(P<0.05) after ST3GAL5 overexpression in bladder cancer. Conclusion ST3GAL5 gene might act as an oncogenic suppressor gene in bladder cancer, possibly inhibit the proliferation, invasion and metastasis of bladder cancer cells by activating the PPAR signaling pathway and inhibiting related molecules in the PI3K/AKT signaling pathway.