By means of multivariate calibration curve, a simultaneous determination of six synthetic colorants including ponceau 2R, sunset yellow, quinoline yellow, basic orange, alizarin green and diamine green B has been achieved by using the partial least squares-spectrophotometric method. Effects of primary parameters such as pH values, additivity of the absorbance of different components, number of principal components in the mathematic model and the wavelength range for spectrophotometric measurement have also been investigated. Under the optimal conditions, the simultaneous determination of six synthetic colorants mentioned above was obtained and the detection limits of 0.2, 0.3, 0.07, 0.2, 2.6, 2.1 μg/mL were gained resp. Applied to simulation samples, the recoveries were found in the range from 98.2% to 104.4%. The method in this work is simple and might provide a new approach to multi-component statistic anal. of these six colorants without any preliminary chem. separation