Abstract: In order to meet the requirements of objective, accurate, and high-precision measurement of laser damage threshold of thin films, the calibration technology of damage threshold was proposed. Firstly, the experimental calibration method of exchanging the positions of the two energy detectors was used to eliminate the error of the spectroscope and the measurement of the energy detector, so as to obtain the accurate irradiation energy. Then, the measurement method of adjusting the positions of two CCD devices to obtain the same spot size was used to calibrate the equivalence between the measured sample surface and the spot area measurement surface, and the non flat top part of the laser spot was eliminated, so as to obtain the accurate irradiation spot area. Finally, the least square method was used to fit the calculated energy density and the corresponding damage probability to obtain the damage threshold. The 1064nm laser irradiation experiment of TiO₂/SiO₂ high reflection film was carried out, and the laser damage threshold was 23.0164J/cm². The results show that the measurement accuracy of laser damage threshold is increased by 9.26% by using calibration technology, which meets the high precision measurement requirements. This study is helpful for accurate calibration of laser damage threshold of thin films.