Solitary fibrous tumors (SFTs) are an uncommon neoplasm characterized by the proliferation of spindle cells. The diagnostic criteria of malignant solitary fibrous tumors (MSFTs) include high cellularity, high mitotic activity (4>10 HPF), pleomorphism, hemorrhage and necrosis. This tumor frequently involves the pleura and MSFTs of retroperitoneum mimicking gastric submucosal tumor are very rare. We report a rare case of MSFT that presented as a gastric submucosal tumor. A gastroscopic examination showed a large bulging mucosa in the gastric body. Abdominal computed tomography revealed a well-defined heterogeneous enhancing mass between the left hepatic lobe and gastric body. Surgical resection was performed and histologic features were consistent with a MSFT.