A rare case of maxillary sinus-originated malignant hemagiopericytoma of a 71-year old female was reported. The tumor extended to pterygopalatine fossa with destruction of the alveolar process, maxillary bone, orbital floor, and zygomatic bone. She underwent tumor extirpation and hemimaxillectomy with resection of the orbital floor and zygomatic bone, and 65Gy of ⁶⁰ Co irradiation was performed after local treatment. A reconstruction of the orbital floor using a titanium mesh tray and forearm flap was performed. Following these therapies, she underwent two courses of adjuvant chemotherapy with Adriamycin, Ifosfamide, and Mesna. Although the disease was locally controlled distant metastases developed in a lung and a thoracic vertebrae.