Abstract: Objective : To investigate the clinical and pathological features and differential diagnosis of alveolar soft part sarcoma (ASPS). Methods : We retrospectively analyzed the data from 30 cases of ASPS.Samples from all 30 cases were examined after H&E staining, and 20 cases underwent detection with immunohistochem-istry (SP method). Results : The male to female ratio was 1:1, and the average age was 30.2 years (ranged from 5 to 67 years).The lesions were mainly located in the deep skeletal muscle of the lower limbs.In the soft tissue, ASPS presented as painless mass.ASPS in the bone caused destructive lesions.ASPS presented as a round or oval mass with a cut surface of yellowish white to grayish red that was often accompanied by hem-orrhage and necrosis.The microscopic appearance showed an organoid and pseudoalveolar proliferation of large eosinophilic cells, separated by fibrovascular septa and delicate capillary-sized vascular channels.The tumors were composed of large cells with eccentric nuclei with abundant eosinophilic granules and crystals in the cytoplasm.Intravascular extension and infiltration to skeletal muscle were also found.Few fibrous tissues were seen in the interstitium.Tumors from patients with a longer clinical course were found with more fibrous tissues and hyalinization.Immunohistochemistry showed that 10 cases were diffusely positive for Desmin, 5 cases were positive for Actin, 3 cases were spot positive for SMA, and 2 cases were spot positive for Vi-mentin.CK and S-100 were negative in all cases. Conclusion : ASPS is a unique neoplasm in adolescents and young adults with a slow progression, early hematogenous metastases, and a high recurrence rate after con-servative surgical excision.Therefore, the prognosis of ASPS is poor.Careful analysis of the clinical and pathological features will be helpful to gain an accurate diagnosis.