We developed robust flexible Cholesteric LCDs with polymer walls using polymerization-induced phase separation. It was found out that phase separation temperature in addition to monomer concentration and UV irradiation conditions affected not only the phase separation degree but also the reflective properties. We investigated the reflective properties of the Ch-LC cell with well separated polymer walls, particularly focused on the temperature dependence, resulting in the viewing angle dependence, of reflectance and reflection wavelength bandwidth. The experimental data for the viewing angle dependent reflection wavelength bandwidth were well fitted by a theoretical modeling with a parameter of alpha, where Delta lambda(theta) = Delta lambda/cos(alpha theta).