Objective To investigate CT and MR appearances of undifferentiated pleomorphic sarcoma in soft tissue, in order to improve diagnostic accuracy. Methods CT and MR images of 32 patients with histologically proved UPS were reviewed, CT and MR imaging findings were correlated with histologic findings. Results Of the 32 UPS cases, There were three different pathological subtypes: ①high grade type 27 cases; ②giant cell type 3 cases; ③inflammatory type 2 cases. Undifferentiated pleomorphic sarcoma were lobulated or irregular Oval shape in all 32 lesions. 27cases with high grade (HG) type and 3cases with giant cell (GC) type, the masses showed heterogeneous density and signals with ill defined margin．Necrosis and cystic degeneration in tumors were often found. The solid component was markedly heterogeneous enhanced. 2 lesions accompanied by hemorrhage and cystic degeneration displayed in 3 cases with giant cell (GC) type. 2cases with inflammatory (In) type had clear border, hemorrhage and cystic degeneration in tumors were uncommmon found．the tumors enhanced slightly after contrast medium. Conclusion CT and MRI findings of undifferentiated pleomorphic sarcoma in soft tissue are varied, The imagings characteristics were different related to their different pathological subtype features, There are some characteristic manifestations in HG type and GC type. But In type do not have specific imaging signs, and the diagnosis need pathologic examination.