ObjectiveTo explore the application value of infrared thermography (IRT) technique assisted peroneal artery perforator flap in repairing oral and maxillofacial defects. MethodsThe clinical data of 20 patients with oral and maxillofacial malignant tumors treated with peroneal artery perforator flap between October 2020 and December 2021 were retrospectively analysed. There were 13 males and 7 females, with an average age of 56.5 years (range, 32-76 years). There were 8 cases of tongue cancer, 5 cases of parotid gland cancer, 4 cases of buccal cancer, and 3 cases of mandibular gingival cancer; and 12 cases of squamous cell carcinoma, 3 cases of adenoid cystic carcinoma, and 5 cases of mucoepidermoid carcinoma. Color Doppler ultrasound (CDU) and IRT technique were performed before operation to locate the peroneal artery perforator and assist in the design of the flap. The sensitivity, specificity, positive predictive value, and negative predictive value of CDU and IRT technique were compared with the actual exploration during operation. The accuracy of CDU and IRT technique in detecting the number of peroneal artery perforator and the most viable perforating points was compared. The patients were followed up regularly to observe the recovery of donor and recipient sites, the occurrence of complications, and the recurrence and metastasis of tumors. Results The sensitivity, specificity, positive predictive value, and negative predictive value of peroneal artery perforators detected by IRT technique before operation were 72.22%, 50.00%, 92.86%, and 16.67% respectively, which were higher than those by CDU (64.17%, 33.33%, 84.62%, and 14.29% respectively). Forty-five peroneal artery perforators were found by CDU before operation, and 35 were confirmed during operation, with an accuracy rate of 77.8%; 43 “hot spots” were found by IRT technique, and 32 peroneal artery perforators were confirmed within the “hot spots” range during operation, with an accuracy rate of 74.4%; there was no significant difference between the two methods (χ²=0.096, P=0.757). The accuracy rates of the most viable perforating points found by CDU and IRT technique were 80.95% (17/21) and 94.74% (18/19), respectively, and there was no significant difference between them (χ²=0.115, P=0.734). The localization errors of CDU and IRT technique were (5.12±2.10) and (4.23±1.87) mm, respectively, and there was no significant difference between them (t=1.416, P=0.165). All the perforator flaps survived, and the incisions of donor and recipient sites healed by first intention. All patients were followed up 5-18 months, with an average of 11 months. The skin flap was soft and had good blood supply, and the lower limb scar was concealed and the lower limb had good function. No lower limb swelling, pain, numbness, ankle instability, or other complications occurred, and no tumor recurrence and metastasis were found during the follow-up. Conclusion Compared with the CDU, using the IRT technique to assist the preoperative peroneal artery perforator flap design to repair the oral and maxillofacial defects has a high clinical application value.