A new method for the non-destructive quantitative measurement of subsurface damages (SSDs) within glass samples is proposed based on the spectral-domain optical coherence tomography (SDOCT) technology. The imaging principle and characteristics of the built SDOCT system are illustrated. The reconstructed two- and three-dimensional images of glass SSDs are given, from which the depths, sizes and shapes of glass SSDs can be obtained quantitatively. These results have significant importance for the manufacture and the applications of optical components.