As the world has a rapidly growing aging population, more and more attention must be paid to product design and development for older adults. Designer should understand the change of aged function, so that they can design product which can satisfy older adults need. Experiment investigated the effects of color combinations of text/background on reading performance. Results showed that nine better color combinations of text/background, including orange/indigo, yellow/red, yellow/green, yellow/indigo, green/white, indigo/yellow, white/red, white/green and white/blue, however, two bad color combinations of text/background, including green/orange and green/blue. Results of this study can be widely applied to various product interfaces, e.g. test displayed on computer monitors, tablet PC interfaces, touch screens, and electronic directories.