Abstract: Phase-locked infrared coating thickness detection technology has the advantages of non-contact and surface measurement, and has broad application prospects. In this paper, the phase-locked infrared coating thickness detection parameters were optimized by using variable thickness coating specimens, the phase-locked infrared coating thickness detection calibration curve was established, and the coating thickness detection qualification requirements and requirements based on phase-locked infrared thermal imaging technology were formulated. Finally, the accuracy and effectiveness of the coating uniformity evaluation method based on lock-in infrared thermal imaging technology were verified by experiments.