The invention relates to the composite optical element and hologram preparation. Wherein, the optical element applies transparent material as substrate with three symmetrical-arranged holographs; the included angle between two holographs is 120deg. The preparation device for the holograph comprises a laser, a spectroscope on the laser outlet to divide the laser into the objective light and the reference light, a reflector on reflection path of the spectroscope, two beam-expand space filters the transmitted light path and reflection light path, collimation lens on output light of the filter path, and a hologram record dry plate, and a dry plate on light path paralleled with the objective and reference lights. |