Spectrum-based rendering uses spectral distributions instead of just three RGB colors for representation of light sources and surface properties in rendering equation. Since, spectrum has a value at every visible wavelength, the spectrum-based rendering gives much accurate color computation compared to RGB-based rendering and it give us opportunity to simulate wavelength dependent phenomena and effects caused by spectrum difference. We introduce a novel framework for spectrum-based rendering on GPU (Graphics Processing Unit) to compute local illumination. On this framework, the Phong reflectance model is implemented employing the spectral power distribution of light source and the spectral reflectance of surface simulating the color rendition of light sources and metamerism of surfaces. Multilayered thin film interference effects can also be handled within this framework with interactive speeds. Additionally, we propose the area light source defined by the spectral cube environment map and show the method for conversion of RGB environment map into a spectral one.