The diagnosis of bladder cancer is established by combining the patient’s symptoms and signs, laboratory and imaging findings, and intraoperative pathological support is required to confirm the diagnosis.1 Symptoms and signs Intermittent and painless hematuria is the most common symptom of bladder cancer, which can be manifested as The time of occurrence of hematuria and the amount of bleeding are not consistent with the malignancy, stage, size, number and morphology of the tumor. Another common symptom of bladder cancer is urinary frequency, urinary urgency and painful urination, which are often associated with diffuse carcinoma in situ or infiltrative bladder cancer, while stage Ta and T1 tumors do not have such symptoms. Other symptoms include pain in the lumbar region due to ureteral obstruction, edema in the lower limbs, pelvic mass, and urinary retention. Weight loss, renal insufficiency, abdominal pain or bone pain are all symptoms of advanced stage. Transrectal, transvaginal finger examination and anesthetic lower abdominal duplex examination have limited diagnostic value in Ta and T1 stage bladder cancer, and there are usually no positive signs. Palpable pelvic masses are mostly evidence of locally progressive tumors. Huang Shiming, Department of Urology, Qianfo Mountain Hospital, Shandong Province, China 2 Laboratory tests 2.1 Urine exfoliative cytology Urine exfoliative cytology is a simple, noninvasive and highly specific method, and is the main method for bladder cancer diagnosis and postoperative follow-up. The sensitivity is 13%-75% and specificity is 85%-100%. 2.2 Ultrasonography Ultrasonography can not only detect bladder cancer, but also help to stage bladder cancer and understand whether there are local lymph node metastasis and surrounding organs invasion, especially for those who are allergic to contrast agent. Ultrasound can be performed transabdominally, transrectally or transurethrally, and transrectal ultrasound shows bladder triangle, bladder neck and prostate more clearly. Transurethral ultrasound is less widely used and requires anesthesia, but the images are clear and the staging accuracy is higher. 2.3 Cystoscopy and biopsy Cystoscopy is the most reliable method to diagnose bladder cancer, which can detect bladder tumors and clarify the number, size, shape and location of tumors, and biopsy can be performed on tumors and suspicious lesions to clarify the pathological diagnosis. When the urinary exfoliative cytology is positive or the bladder mucosa is abnormal, selective biopsy is recommended to clarify the diagnosis and understand the extent of the tumor. If available, flexible cystoscopy is recommended, which has the advantages of minimal injury, no blind field of view, and comfortable examination position. 2.4 Diagnostic transurethral resection (TUR) TUR has been gradually adopted as the preferred method for the diagnosis of bladder cancer. If imaging reveals tumor lesions in the bladder and there are no obvious signs of bladder muscle infiltration, cystoscopy can be omitted at discretion and diagnostic TUR can be performed directly under anesthesia, which can achieve two purposes: first, resection of the tumor, and second, histological examination of the tumor specimen to clarify the pathological diagnosis, tumor grading and staging, and provide a basis for further treatment and prognosis.3 Imaging Examination 3.1 CT examination CT has some value in the diagnosis of bladder tumor and can detect larger tumors and can also be distinguished from blood clots. However, smaller tumors (e.g. <5mm) and carcinoma in situ are still not easily detected, the ureter cannot be understood, the accuracy of staging is not high, enlarged lymph nodes cannot be distinguished from metastases or inflammation, and it cannot accurately distinguish whether the tumor is confined to the bladder or invaded outside the bladder. Therefore, CT can be performed if the tumor is found to be substantial (non-tip), has the potential to infiltrate the muscular layer, or if there are liver lesions. 3.2 MRI MRI is more accurate than CT or unenhanced MRI for staging tumors. T2-weighted images show high signal in the urine, low signal in the normal detrusor muscle, and moderate signal in most bladder cancers. The interruption of the tumor beneath the low-signal pushing muscle suggests muscle infiltration. In terms of staging, MRI with intensifier can differentiate non-muscle infiltrating tumors from muscle infiltrating tumors and the depth of infiltration, and can also detect signs of metastasis in normal-sized lymph nodes. The sensitivity of MRI is much higher than that of CT and even higher than that of nuclear bone scan in detecting bone metastasis. 3.3 Other imaging tests can be used at clinical discretion, including chest X-ray, chest CT, plain radiographs and intravenous urography of the urinary system, bone scan, PET (positron emission tomography), 5 ALA fluoroscopy cystoscopy, etc. In conclusion, for patients with suspected bladder cancer, medical history, physical examination, urine routine, ultrasound, urine exfoliation cytology, IVU examination and chest X-ray should be performed. Cystoscopy and pathological biopsy or diagnostic TUR should be performed for all patients with suspected carcinoma in situ and positive urinary exfoliative cytology without clear mucosal abnormalities, and random biopsy should be considered. Pelvic CT/MRI and bone scan are optional for patients with muscle-infiltrating bladder cancer as needed.