Abstract: Using two-dimension finite-difference time-domain (2D-FDTD) method,the optical fields of solid immersion lens are studied when ill uminated by linear polarized focusing Gaussian beam.The simulated results reveal that the portrait optical field is produced,which broadenes the emitted beamradius.The beam of the component field whose polarization is parallel to the incid ent beam is smaller than that of the total optical field and the higher the refractive index is,the larger the contrast is.