The effect of an apodizer with two parallel taper refractive surfaces is theoretically investigated for highdensity optical storage. The apodizer may modulate an incident Gaussian beam into an annular beam. Simulation shows that with the increasing inner radius of the modulated beam, the focal spot shrinks obviously. The depolarization effect gets strong simultaneously, which induces the circular symmetry loss of the focal spot. In this process, pattern density of the orthogonal and longitudinal diffractive fields increases remarkably. The effect of an apodizer with two parallel taper refractive surfaces is theoretically investigated for high density optical storage. The apodizer may modulate an incident Gaussian beam into an annular beam. Simulation shows that with increasing increasing radius of the modulated beam, focal spot shrinks obviously . The depolarization effect gets strong simultaneously, which induce the circular symmetry loss of the focal spot. In this process, pattern density of the orthogonal and longitudinal diffractive fields promote remarkably.