A simple GC method with a FID detector was developed in order to determine two main compounds (${eta}$-sitosterol and lupenone) for Adenophorae Radix. ${eta}$-Sitosterol and lupenone were analyzed by the gradient thermal ramping method. Nitrogen was used as the carrier gas at 108 kPa. The flow rate of gas was 2.0 mL/min; $2{mu}L$ of filtered sample was injected at a split ratio of 1 : 80. This method was fully validated with respect to linearity, precision, accuracy and robustness. Further, this GC-FID method was applied successfully in order to quantify two compounds in an Adenophorae Radix extract. The GC analytical method for classification analysis was performed by repeated analysis of 59 reference samples in order to differentiate between Adenophora triphylla var. japonica Hara and 14 Codonopsis lanceolata. The results indicate that the GC-FID method is suitable and reliable for the quality evaluation of Adenophorae Radix.