Objective To investigate the effectiveness of posterior lateral perforator flap in lower limb combined with free fibula for maxillary tissue defect repair. Methods Between December 2018 and December 2023, 16 patients with the maxillary malignant tumors were admitted. There were 10 males and 6 females, with an average age of 64.3 years (range, 54-75 years). There were 7 cases of maxillary gingival cancer, 5 cases of hard palate cancer, and 4 cases of maxillary sinus cancer. According to the 2017 American Joint Committee on Cancer (AJCC) TNM stage, there were 8 cases of stage Ⅲ, 6 cases of stage Ⅳa, and 2 cases of stage Ⅳb. After resection of the lesion, the remaining maxillary defects were classified into class Ⅱa in 3 cases, class Ⅱb in 5 cases, and class Ⅲb in 8 cases according to Brown’s classification. The size of soft tissue defects ranged from 4 cm×3 cm to 8 cm×6 cm. The posterior lateral perforator flap in lower limb in size of 5 cm×4 cm-9 cm×7 cm were harvested to repair soft tissue defects, and free fibula in length of 6-11 cm were used to repair bone defects. The donor sites of the lower limb were sutured directly (6 cases) or repaired with free skin grafting (10 cases). Six patients with positive lymph node pathology were treated with radiotherapy after operation. At 6 and 12 months after operation, the self-assessment was performed by the University of Washington Quality of Survival Questionnaire Form (QUW-4) in five dimensions (facial appearance, swallowing function, chewing function, speech function, and mouth opening), and swallowing function was evaluated by using the Kubota water swallowing test. Results Postoperative pathological examination showed that all patients were squamous cell carcinoma. One patient who was treated with radiotherapy developed osteomyelitis and 1 patient developed venous crisis of skin flap. The rest of the flaps and all skin grafts survived, and the wounds healed by first intention. All patients were followed up 1-5 years (mean, 2.8 years). Two patients died of local recurrence of the tumor at the 4th and 5th years after operation, respectively. Except for the chewing function score and total score at 6 months after operation, which showed significant differences compared to preoperative scores (P<0.05), there was no significant difference in other QUW-4 scale scores between different time points (P>0.05). The patients’ swallowing function evaluated by Kubota water swallowing test reached normal in 4 cases, suspicious in 9 cases, and abnormal in 3 cases at 6 months after operation, and 10, 6, and 0 cases at 12 months after operation, respectively. The swallowing function at 12 months was significantly better than that at 6 months (χ2=6.171, P=0.046). Conclusion The posterior lateral perforator flap in the lower limb combined with free fibula to repair maxillary tissue defects can repair soft and hard tissue defects at the same time, so that the patient’s facial appearance, swallowing function, chewing function, speech function, and mouth opening are satisfactorily restored and the long-term effectiveness is good.