To determine the benignity and malignancy of retroperitoneal tumor, the key relies on pathological histological judgment. Patients with retroperitoneal tumor mainly present with abdominal distension and discomfort or low back pain, and gradually the abdomen is bulging and full. In addition, patients can be found to have occupying lesions in retroperitoneum by ultrasound, CT, MRI or PET-CT. The patient’s tumor proximity is clarified by gastrointestinal tract imaging, angiography, and urography. In such cases, the physician performs a thorough evaluation to determine the patient’s treatment plan. On this basis, pathological histological examination is obtained as much as possible, and coarse needle aspiration biopsy can be performed under ultrasound and CT guidance to determine the pathological nature of the tumor and decide the specific treatment method.