A propagation model for hollow Gaussian beams (HGBs) through the paraxial optical system is derived, the propagation properties of HGBs in free space are analyzed using the derived propagation formula, and the propagation equation is simulated by using Matlab software. The results show that the ordern and propagation distancez are the importance parameters for controlling hollow beams. With the increase of ordern , Gaussian beams are gradually become HGBs, and the center of dark and bright radius of the bright ring are correspondingly increased. With the increase of propagation distancez , HGBs are divergent, and black spot area is reduced in the ratio of the total spot area, but in the far-field the black spot is disappeared, and light intensity becomes the maximum on the axis.