Abstract: The yam powder was prepared by the hot hair drying. The study mainly focused on the relationship of citric acid, ascorbic acid, phytic acid calcium chloride and the whiteness of yam powder, through the method of response surface methodology. The optimum conditions of drying by hot air were:citric acid concentration1.28%, ascorbic acid concentration 0.05%, phytic acid concentration 0.12%, calcium chloride concentration0.3%, under the condition, the Ganz whiteness of the yam powder was 23.56. The results showed that:the optimization of color protection process for yam powder by response surface methodology was reasonable with the Indicator of Ganz whiteness. That was providing a theoretical support for color protection of yam powder.