Objective: To investigate the clinical effect of buccal fat pad flaps on the restoration of maxillary defects. Methods: Nineteen cases with oral-nasal communications and maxillary soft and hard tissue defects ranging from 3.0 cm×2.0 cm-5.0 cm×4.0 cm after resection of the primary tumor foci were repaired with a pedicled buccal fat pad flap, and the maxillary sinus cavity and oral-nasal communication were closed. The survival, healing and complications of the flap were observed during the 3-month follow-up. Results : The buccal fat pad flaps of 19 patients all survived. Five days after the operation, the buccal fat pad flap was dark red with slight edema, and the maxillary defect area collapsed. Ten days after the operation, most of the buccal fat pad flap turned pink, and the collapse was alleviated. One month after the operation, the buccal fat pad flap had no obvious collapse, and its surface was epithelialized, with a shape and color close to those of the normal mucosa. The opening was slightly limited. Three months after the operation, the buccal fat pad flap was completely epithelialized, with no difference from the surrounding tissue, and the opening was approximately 3 transverse fingers. No complications, such as swelling and necrosis of the buccal fat pad flap, limitation of mouth opening, maxillary sinus fistulas, oral-nasal communications and facial changes occurred in 19 patients within 3 months after the operation. Conclusion The application of a buccal fat pad flap has a good effect to repair maxillary tissue defects and close oral maxillary sinus communication with diameters less than 5 cm, so it can be widely used in the clinic.