Abstract: To obtain the visual characteristics of frequency response under uniform-scaled color space and to construct its model, the contrast sensitivity functions of hue (S_H) were tested under CIE1976 L^* a^* b^* system. A series of images with sinusoidal change of hue angle in spatial frequency domain were displayed on a calibrated color display system. A lot of visual observation tests were carried out and 12 S_H functions at corresponding hue angle centers were finally obtained. The test result shows that, under different hue angle centers, the S_H functions are different. The differences among the 12 S_H functions are related to the color distinguishing characteristics of human visual system. Based on the visual test data, the functional model of S_H could be constructed.