Abstract: To cancel the negative influence of the polarization variety of the incident light on a coherent system because,one of the effective methods is to depolarize the incident light.Making use of the characteristic of liquid crystal whose refractive index n along z is various with the deflection orientation of the liquid crystal element,the polarization of the liquid crystal can be arbitrarily controlled by changing the voltage of the liquid crystal and the light can propagate at arbitrary polarization.A new depolarizer composed of two liquid crystal was proposed in the paper.Experimental results show that the liquid crystal depolarizer is insensitive to the polarization state of the incident light and can totally depolarize CW or pulsed monochromatic light with arbitrary polarization states.The depolarizer has the potential to keep the polarization state of the fiber injection laser system of the ICF driver.