The effect of conjugate image in reconstruction of annular aperture rainbow hologram is analysed theoretically and experimentally. The dependence of conjugate image intensity upon the medium depth and the object-reference beam angle is derived. The condition of eliminating conjugate image for conventional 6 μm plates is thus indicated. Based on this principle, the large viewing angle (47°) annular aperture one-step rainbow hologram without interference of conjugate image is realized for the first time.