Abstract: The diffraction equations for continuous subwavelength dielectric polarization gratings are derived using Jones matrix approach. The polarization characteristics and diffraction efficiencies are also discussed. The results show that, by setting up the parameters such as the incident light polarization state and grating phase delay, only three diffraction orders with an arbitrary diffraction efficiencies distribution exist in continuous subwavelength dielectric polarization grating, and the total efficiency of the diffraction orders is always 100%. Moreover, the polarization state of zeroorder wave is identical to the incident wave. Ｔhe polarization state of +１order is a rightcircularly polarized wave and the polarization state of －１order is a leftcircularly polarized wave, bo