The CT manifestation of retroperitoneal liposarcoma is a huge mass in the retroperitoneum with an intralesional hypodense focus, and the MRI manifests a soft tissue solid mass. 1.CT: CT examination can clarify the anatomical location, scope and size of the retroperitoneal space where the tumor is located. Retroperitoneal liposarcoma is often manifested as a huge mass in the posterior abdomen, with irregular morphology and infiltration of peripheral tissues, and it is possible to find fatty low-density foci within it. On enhanced examination, retroperitoneal liposarcoma is mostly unevenly intensified, with no enhancement of the fatty portion within the mass, and mild enhancement of the soft-tissue segregated portion. 2. MRI (magnetic resonance imaging): it is mostly manifested as a soft tissue solid mass, with uneven signal on plain scanning, uneven enhancement of the solid part after enhancement, and the lesion is mostly accompanied by necrosis or segregation, and vascular shadows. Patients with retroperitoneal liposarcoma should go to the hospital in time to improve the relevant examination, make the diagnosis by the doctor, and standardize the treatment under the doctor’s guidance.