Abstract: A set of color coded characters with the same or similar shapes were displayed on the backgrounds of different colors. Search time was tested as a index for evaluating visual performance of color coding for characters and parametric effects of foreground color, background color, character size and illuminant condition on the visual performance in synthesized information displays. The results show that color coding is more effective than shape coding in reducing search time, especially when the character size is small; the time needed for searching color coded characters is related to the color combination of its foreground and background, and generally decrease with the increase of color difference between them.