The large range homogeneous field of a large scattering slit can be used to make marking′s large viewing rainbow hologram. Cutting the Gaussian field into two symmetrical light fields and overlapping them in a frosted glass, thereby the large range homogeneous field is obtained. The optical system using the general reflection devices is presented and analysed. The new optical setup can obtain more homogeneous brightness in the large-range field. The satisfactory experimental results have been obtained.