Three species, such as Rheum palmatum L., R. tanguticum Maxim. and R. officinale Baillon are recognized as the source plants of Rhei Rhizoma in Korean Pharmacopeia. However, other herbal sources such as R. undulatum L. and Rumex crispus L. have been often misused as Rhei Rhizoma. A pattern analysis method to discriminate Rhei Rhizoma in Korean Pharmacopeia from other herbal plants using HPLC and TLC chromatograms was developed. The multivariate peak data of the chromatograms of methanol extracts of Rhei Rhizoma were used for hierarchical clustering analysis, principal components analysis and similarity calculation. Besides of the statistic analysis, TLC patterns of samples could be used as criteria of the discrimination. The developed pattern analysis method was specific and could be readily utilized for comprehensive evaluation of Rhei Rhizoma.