Objective: To explore the clinicopathologic features, diagnosis and differential diagnosis, treatment and prognosis of malignant solitary fibrous tumor (MSFT). Methods: The clinical data, histopathological features, immunophenotype, treatment and prognosis of nine cases of MSFT were reviewed. Results: The patients included 6 males and 3 females with average age of 54 years. Three cases had intracranial tumors, one case had tumor in lung, one in retroperitoneal, one in left upper abdomen, one in pelvic, one in orbital and one in left thigh. Under the microscope, tumors of four cases were composed of epithelioid cells and spindle cells with a distribution of alternate density, hemangiopericytoma-like structure and interspersing collagen fibers. Tumor cells in two cases showed uniformly round or polygonal epithelioid cells in high density. Tumor cells in two cases were the diffused spindle cells arranged in braided, ribbon and fishbone-like structures without alternating density areas. Tumor cells in one case were short spindle cells in both of hypocellular and hypercellular with palisade structure and myxoid background. Tumor cells of nine cases showed significant cell atypia and mitoses (more than 4/10 HPF). Hemorrhage and necrosis could be seen in some cases. Considering immunophenotype, the tumor cells showed positive staining for CD34 and Vimentin in nine cases, positive staining for CD99 in four cases and positive staining for Bcl-2 in four cases. The recurrence appeared in five cases after surgery. Conclusion: MSFT is a rare malignant soft tissue tumor and the diagnosis of the tumor requires a comprehensive judgment of morphology and immunophenotype. Surgical resection is the first choice of treatment, but the recurrence rate is high.