A micron spectral domain optical coherence tomography (SDOCT) system built by us is used to conduct depth resolution, noncontact, and nondestructive measurement of glass subsurface defects. In addition, a single scattering model is used to calculate the obtained tomographic images, and obtain the glass scattering coefficient of glass subsurface defects. The experimental results revealed that the use of scattering coefficient is effective in distinguishing damage structures at different depths on the glass subsurface. The depth resolution measurement of the glass subsurface scattering coefficient is beneficial to the analysis of the optical characteristics of glass subsurface defects, and is essential for the processing and testing of precision optical components.