PET-CT diagnosis suggests a high likelihood of multiple lymph node metastases and has a high likelihood of confirming the diagnosis in patients with tumors. PET-CT, also known as positron emission computed tomography, is a test that determines whether a tumor is metabolically active by measuring the amount of contrast uptake in the lesion. It can accurately determine the benign or malignant nature of most tumors, whether there is metastasis, and achieve early diagnosis. If there is a history of tumor, multiple lymph nodes are found through examination, and the lymph nodes themselves show obvious uptake of contrast medium, suggesting that the cells in them are metabolically active, then the diagnosis of multiple lymph node metastasis is highly probable, and the diagnosis is generally confirmed. Diagnosis of multiple lymph node metastasis by PET-CT requires a combination of other tests, such as blood tests, to make a comprehensive judgment of the lesion. After the diagnosis is confirmed, standardized treatment should be carried out under the guidance of clinicians to avoid delaying the condition.