We propose here a novel multi-layered waveguide liquid crystal (LC) smart window with full color rendering based on a polymer-network liquid crystal system. The inserted position of three-primary-color LED light bars is specially designed, which is parallel to the LC alignment to obtain a higher difference between transparent and scattering states. The optimal matching of polymer-network LC system is experimentally achieved by comparing several groups of LC and reactive mesogen materials. The prepared smart window is measured and analyzed in detail including optical/chromatic test, morphology characterization, and actual application effect. The proposed architecture opens up new prospects of flexible color switchable ability and synchronized full-color display for smart windows without limitations of slow LC response time and complicated field sequential driving scheme.