Objective: To determine the color of Arnebiae Radix, and the contents of six main purple pigment components (acetylshikonin, β-acetoxyisovalerylalkannin, deoxyshikonin, isobutylshikonin, β, β’-dimethylacrylalkannin and isovalerylshikonin) in Arnebiae Radix, and to study on the correlation between the color of Arnebiae Radix and the contents of six main purple pigment components. Methods: The L, a, and b values of the sample powder were determined using a spectrophotometer to characterize the color of Arnebiae Radix. The International Commission on Illumination (CIE) had developed a Lab color model, which was a digital description of human vision. A higher L value indicated greater brightness, a higher a value indicated redness and a lower a value indicates greenness, and a higher b value indicated yellowing and a lower b value indicates blueness. The contents of purple pigment components were determined using high performance liquid chromatography (HPLC), and the correlation between L, a, and b values and the contents of six main purple pigments was calculated using SPSS software. Results: The contents of acetylshikonin in 135 batches of samples ranged from 0.01% to 3.39%. The contents of β-acetoxyisovalerylalkannin ranged from 0.00% to 1.95%. The contents of deoxyshikonin ranged from 0.00% to 0.23%. The contents of isobutylshikonin ranged from 0.01% to 1.13%. And the contents of isovalerylshikonin ranged from 0.02% to 2.88%. The contents of β, β’-dimethylacrylalkannin ranged from 0.01% to 2.17%. There was a significant negative correlation between the contents of acetylshikonin, β-acetoxyisovalerylalkannin and isobutylshikonin and the L (black_white) chromaticity value of Arnebiae Radix, with a Spearman correlation coefficients between -0.138 and -0.222. The chromaticity value of a (red_green) was related to the five components other than acetylshikonin, which were β-acetoxyisovalerylalkannin, deoxyshikonin, isobutylshikonin, β, β’-dimethylacrylalkannin, and isovalerylshikonin, with a spearman correlation coefficients between 0.176 and 0.355; b (blue_yellow) chromaticity value was related to the five components other than β-acetoxyisovalerylalkannin, which were acetylshikonin, deoxyshikonin, and isobutylshikonin, β, β’-dimethylacrylalkannin. β, β’-dimethylacrylalkannin was positively correlated with a coefficient of 0.290, and negatively correlated with the other four components with a coefficients between -0.325 and -0.633. Conclusion: It is recommended that the assay limits of Arnebiae Radix be revised to β, β’-dimethylacrylalkannin not less than 0.30% and isovalerylshikonin not less than 0.29%.