Objective To explore the effect of facial artery musculo-mucosal (FAMM) flap to reconstruct tongue and floor of mouth defects. Methods Between January 2011 and January 2016, 24 cases of tongue and floor of mouth defects were repaired with FAMM flap after tumor resection. There were 16 males and 8 females, aged from 38 to 70 years with an average of 55 years. The disease duration was from 1 week to 6 months with an average of 4 months. The defect located at the floor of mouth in 4 cases, at the tongue in 15 cases, and both tongue and floor of mouth in 5 cases. There were 2 cases of carcinoma at the floor of mouth, 2 cases of adenoid cystic carcinoma at the floor of mouth, 14 cases of carcinoma at the tongue, 1 case of adenoid cystic carcinoma at the tongue, and 5 cases of carcinoma at the tongue and floor of mouth. The size of defect ranged from 4 cm×3 cm to 8 cm×7 cm. Three ipsilateral and 21 contralateral FAMM flaps were harvested (5 cases were repaired with FAMM flap and submental muscle island flap due to the large defect area). The size of FAMM flap ranged from 5 cm×4 cm to 5 cm×5 cm, the size of submental muscle island flap ranged from 4 cm×3 cm to 5 cm×4 cm. Results All flaps survived after operation, without local necrosis. Wound dehiscence at donor site occurred in 5 cases, and healed after cleaning; primary healing was obtained in the other 19 cases. All the patients were followed up 8 months to 5 years with an average of 2 years and 4 months. No obvious facial deformity or fistula of the floor of mouth occurred after operation. Injury of the submandibular branch of the facial nerve was observed in 16 patients, who returned to normal at 3 months. All 24 patients had limitation of mouth opening after operation, which disappeared after 12 months. The functions of speech, chewing, and swallowing were normal. Conclusion FAMM flap has many advantages of simple operation, good repair, high flap survival rate, and less injury at donor site for repairing tongue and floor of mouth defects.