Objective · To explore the effect of infrared thermography (IRT) on detecting the dominant supratrochlear artery in nasal reconstruction using expanded forehead flaps. Methods · Fifteen patients who planned to use the expanded forehead flap for nasal reconstruction were selected. Preoperatively, IRT was used to mark the supratrochlear artery in the expanded flap to determine whether the blood vessel was missing and whether the quality of the bilateral vessels was symmetrical. The results were verified by color ultrasonic Doppler blood flow imaging. According to the result of preoperative vessel detection, the supratrochlear artery on the dominant side was selected to design the flap. Results · All 15 flaps could be marked with IRT to identify the supratrochlear artery. Among them, 10 cases had symmetrical vascular calibers and flow velocity, 2 cases had unilateral vascular deficiency, and 3 cases had asymmetric vascular quality. The supratrochlear artery on the dominant side was used as the pedicle, and flaps with the size of 4 cm×6 cm- 6.5 cm× 13 cm were excised, and all flaps survived well. Conclusion · There is the possibility of bilateral vascular asymmetry in the expanded forehead flap. The use of IRT can quickly identify the dominant supratrochlear artery and ensure the blood flow after the flap is elevated.