Color asymmetry is a common phenomenon in 3D displays, which can cause serious visual discomfort. To ensure safe and comfortable stereo viewing, the color difference between the left and right eyes should not exceed a threshold value, named comfortable color difference limit (CCDL). In this paper, we have experimentally measured the CCDL for five sample color points which were selected from the 1976 CIE u'v' chromaticity diagram. By human observers viewing brief presentations of color asymmetry image pairs, a psychophysical experiment is conducted. As the color asymmetry image pairs, left and right circular patches are horizontally adjusted on image pixels with five levels of disparities: 0, ±60, ±120 arc minutes, along six color directions. The experimental results showed that CCDLs for each sample point varied with the level of disparity and color direction. The minimum of CCDL is 0.019Δu' v' , and the maximum of CCDL is 0.133 Δu' v'. The database collected in this study might help 3D system design and 3D content creation.