The diffraction efficiency of reflection hologram is theoretically calculated by using the character matrix of multilayer medium films.The polarization characters of reflection holographic grating recorded in dichromated gelatin is discussed,while the diffraction properties are analyzed respectively for p polarized light and s polarized light by computer simulation.Experimental results are presented.We see that the diffraction efficiency of reflection hologram can be highly dependent on the polarization of incident light.In conclusion,the way to choose right polarization component in practical application is brought forward.