Case 1: A patient with prostate cancer, 67 years old, with a history of previous panic attacks and chest tightness, and no abnormalities in the electrocardiogram on preoperative examination. The patient was found to have coronary stenosis after dual-source CT examination and was immediately transferred to cardiology for stent intervention. One week later, the patient’s condition stabilized and he was transferred to urology for radical prostate cancer surgery. Case 2: A patient with bladder tumor, 60 years old, with a history of old heart infarction, preoperative examination showed ST-T segment downward shift of electrocardiogram, considering the risk of surgery, we performed preoperative evaluation for this patient. The patient was found to have severe left anterior descending branch stenosis after dual-source CT examination and was immediately transferred to cardiology for stent intervention. One week later, the patient was stabilized and transferred to urology for total cystectomy. The prerequisite for surgical procedures is anesthesia, and it is very important that the patient can smoothly pass the anesthesia barrier. Effective preoperative assessment of cardiac function and proper management can avoid intraoperative and postoperative risks. The above case is the benefit of preoperative assessment, please pay attention to preoperative assessment.