Abstract: Green rind is one kind of the quality defects of potato. This paper put forward a method based on the hue threshold to detect green rind of potato, and extract the color information from the quantitative perspective. The models of stepwise discriminated analysis based on the statistical and support vector machine have disadvantages of the unsteady results due to the limitations of characteristics space of a particular sample set. To overcome the foregoing methods shortcomings, the new method extracted hue as features, confirmed effective range of hue 57 to 64 which could distinguish normal potatoes and greened ones. With the second threshold discrimination, the results showed that the method had the characteristics of simple, high detection accuracy rate and stable.