Objective: To investigate the morphologic features of alveolar soft-part sarcoma (ASPS) and its differential diagnosis. Methods: The clinical data were retrospectively analyzed in 4 cases of ASPS. Histopathological and immunohistochemical changes of the tumors were also observed in the paraffin-embedded tissue samples. Results: Three cases were male, 30, 25 and 27 years old respectively; 1 case was female, 34 years old. The lesions were mainly located in the deep soft tissues of legs. Microscopically, tumor cells with granular cytoplasm arranged in alveolar or solid structures, and were separated by sinusoidal vessels. Needle-like crystals were detected in the cytoplasm of tumor cells. Immunohistochemically, 4 cases were positive for TFE3 and 3 cases were positive for MyoD1. One patient died with recurrence and pulmonary metastasis after 15 years, three patients were followed up for 6 months without neoplasm survival. Conclusion: Alveolar soft part sarcoma is a rare malignant neoplasm in young adults. By combining with clinicopathological features and immunohistochemistry, excluding alveolar rhabdomyosarcoma and some adenocarcinomas as differential diagnosis, a correct pathological diagnosis can be made. TFE3 antibody is a useful marker in the pathologic diagnosis of ASPS.