Myeloid sarcoma (MS), also known as granulocyte sarcoma, is a malignant extramedullary tumor composed of immature myeloid cells. MS can occur de novo, but more commonly occurs in patients with acute myeloid leukemia, myeloproliferative disorder, and myelodysplastic syndrome, or in the acute phase of chronic myeloid leukemia, or as a manifestation of disease relapse. MS can occur in any part of the body, causing different clinical manifestations. The more frequent sites in children are skin and orbit. The diagnosis of MS relies on the combination of clinical manifestation, radiology, histology, immunohistochemistry, cytogenetic and molecular genetic analyses. After diagnosis, systemic chemotherapy is recommended as early as possible. Surgical resection and radiotherapy can relieve obstructive or compressive symptoms caused by tumors in specific sites. The prognosis of MS depends mainly on its subtype and genetic abnormalities. This article reviews the pathogenesis of MS, clinical characteristics, diagnostic and therapeutic strategies and prognosis of MS in children.