In this paper, the mechanism and the basic theory of producing holographic volume grating within the polymer dispersed liquid crystal film are expounded. Some experiments were conducted to investigate the micro structure of the H PDLC grating, major factors impacting the diffraction efficiency of grating, such as different recipes of PDLC, the degree of two laser beams, thickness of film, exposing time of PDLC cells and the applied voltage. As a result, it is found that the most significant affecting factor is the recipe of PDLC. With the same recipe, shorter cure time, comparative smaller degree of two laser beams and thinner PDLC film give rise to higher diffraction efficiency. Finally, using 17 degree of two laser beams, 10 μm of PDLC film thickness, 50 mW power of laser with the wavelength of 441 6 nm and exposing time about 30 seconds, the efficiency of about 90% of the H PDLC volume grating is obtained.