Abstract: This paper deals with the selection of optimal system combination for the chromatographic separation of 13 barbiturates from 14 kinds of TLC systems by stepwise combination method (Ⅰ). The experimental results are excellent. By increasing the d value, an absolutely optimal system combination may be obtained. The method (Ⅰ) is better than NT-I, SD-I, CD-WPG, CA-I and RSTWPG methods in its simplicity and convenience.