A model of optics component damage induced by a spherical inclusion in fused silica illuminated by a laser beam is developed. Based on Mie scattering theory, scattering coefficients of several common kinds of inclusions are calculated, the light field distributions in the vicinity of inclusions are simulated. Light intensity enhancement factor (LIEF) as functions of refractive index and radius are analyzed. The results show that modulation effect of all kinds of inclusions can be ignored when the radius is smaller than 40 nm; when the radius of the particle is larger than 40 nm, for a non-dissipative particle with refractive index less than that of fused silica, LIEF increases with increasing radius and decreases with increasing refractive index, and the backscattering is much stronger than the forward scattering; when the refractive index is greater than that of fused silica, LIEF increase with the increasing radius and refractive index, and LIEF can reach to the order of 102 in some situations. For a dissipative particle, with the increase of radius, forward scattering intensity increases at first and then decreases. When the radius is larger than 170 nm，backscattering intensity is greater than forward scattering intensity.