The inferiorly based buccinator myomucosal island flap is a useful reconstructive option for intraoral mucosal defects. The present study suggests a patient with hard palate tumor shown a partial erosion of alveolus on left last molar tooth. However, the tumor did not invade into nasal cavity mucosa on preoperative radiologic images. therefore, we planned wide resection of hard palate tumor with palatal bone for En-bloc resection and preserved the periosteum and mucosa of nasal side of hard palate. Subsequently, the defect was successfully reconstructed with inferiorly based buccinator mycomucosal island flap. The patient has no evidence of disease and complication such as oronasal fistula. Therefore, we suggest the feasibility of this flap with literature review.