In general, the bladder mucosa is slightly thickened and less smooth, which is considered to be caused by cystitis, bladder tumor and so on. (1) Cystitis: refers to inflammatory lesions of the bladder caused by bacterial infection as well as other non-bacterial infectious factors such as stones and foreign bodies, etc. Bacterial cystitis is more common and mainly manifests as bladder irritation signs such as urinary frequency, urinary urgency and urinary pain. The bladder mucosa is stimulated by bacteria such as Escherichia coli, drugs such as cyclophosphamide, stones, foreign bodies, etc., which cause localized inflammatory hyperplasia of the mucosa and lead to non-smooth inner wall. (2) Bladder tumor: refers to tumors occurring in the bladder, mostly located in the bladder triangle and the lateral wall of the bladder, the main symptoms are hematuria, dysuria and bladder irritation signs such as urinary frequency and urgency. They can be classified as benign and malignant tumors. The histological classification is epithelial-derived tumors, non-epithelial-derived tumors, miscellaneous tumors, metastatic tumors, and secondary tumors. Tumor cells irritate the bladder mucosa causing thickening. The bladder mucosa is slightly thickened and not smooth, it is recommended to consult a doctor for a clear diagnosis and targeted treatment under the doctor’s guidance.