In the paper, a holographic storage experiment on laser optically induced light diffraction in acrylamide photopolymer thin film is reported, in which the semiconductor laser of 532nm is used as writing and reading light source, and fuchsin basic is used as sensibilizer. The appearance of diffraction rings can readily be explained as being holographic interference fringes formed by the original laser beam and light scattered from internal or surface inhomogeneities in the unexposed photopolymer. According to phase match condition of degenerate four-wave mixing theory, the diffraction cones of double laser beam holographic writing and single laser beam radiative reading are explained separately. The relationship between angle of incidence and diffraction cone angle is deeply studied by using holographic scattering theory with the help of trigonometric functions.