Optical component damage is one of the important factors that limit the improvement of laser flux level. To quickly and accurately detect whether optical component damage occurs and support the use of optical component cycle repair strategy, we proposed an optical component damage detection method based on acoustic emission technology. Whether the optical component is damaged was judged by studying the characteristics of acoustic emission signals generated by optical component damage. A time delay estimation algorithm based on quadratic correlation and fine interpolation of correlation peak (FICP) was developed. The feasibility of the algorithm was verified by simulation. Combined with the principle of time difference location, a method for solving the damage location was established and verified by experiments. The results show that the method can quickly obtain the damage location estimation from the monitoring signal. The average positioning error is 8.61 mm, and the average calculation time for positioning is 0.143 s. The method has the potential to be applied to on-line damage monitoring of large-aperture optical components.