In the full-color, high contrast, more accurate color rendition technology, High-Definition (HD) color display requires to increase the transmissivity of red green blue (RGB) light of ordinary white light and cut-off others in depth. The ordinarily used discrete tricolor light filter has shortcomings such as energy lose and polarization aberration. In this paper, a new tricolor light filter was designed and prepared based on thin film technology. The center wavelengths of the tricolor light filter were determined to be λR=700.0nm, λG=546.1nm and λB=435.8nm, the results showed that the transmissivity of the filter is less than 7% in cut-off region, and the average transmissivity is greater than 91% in pass band region. The tricolor light filter can simplify the preparation process, save the coats and increase the transmission property.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.