Abstract: Objective To explore the pathogenesis，diagnosis，treatment and outcome of granulocytic sarcomas. Methods A middle aged male patient with CD56+granulocytic sarcoma in his small bowel as the first presenting sign of acute monocytic leukemia was reported and the relevant literatures were reviewed. Results The male patient was 39 years old. The immunohistochemical findings of small bowel mesenteric excision showed granulocytic sarcoma with positive CD56 antigen. Bone marrow cytology examination showed the feature of acute monocytic leukemia. The patient was diagnosed with acute monocytic leukemia with small intestine myeloid sarcoma. The patient achieved complete hematology remission after IA therapy, and the consolidation chemotherapy of IA regimen was followed then. The allogeneic hematopoietic stem cell transplantation would be applied. Conclusion The acute leukemia with the small bowel granulocytic sarcoma as the first presenting sign is relatively rare. The prognosis of granulocytic sarcoma is poor. CD56 antigen probably suggested the patients poor prognosis. So patient after remission should be as soon as possible to be treated by allogeneic hematopoietic stem cell transplantation in order to achieve the long term survival.