A theoretical model for calculating the diffraction efficiency kinetics of the grating recorded by two parallel circular polarized recording beams was proposed,based on Jones-matrix and photochromic two-state theory.The diffraction efficiency of bacteriorhodopsin grating was measured by system of four-wave coupled light path.The theoreical analysis and the experimental results show that,in the condition of adding linearly polarized auxiliary violet light,when linearly polarized reconstruction light parallel with linearly polarized auxiliary violet light,the diffraction efficiency of bacteriorhodopsin grating is maximum;when linearly polarized reconstruction light perpendicular to linearly polarized auxiliary violet light,the diffraction efficiency of bacteriorhodopsin grating is minimum.The angle between linearly polarized reconstruction light and linearly polarized auxiliary violet light produces a cosine modulation on the kinetics of the diffraction efficiency.It indicates that parallel circular polarization recorded grating in bacteriorhodopsin induced by polarized violet light became polarizing grating.