The volatile constituents obtained from ethanol extracts of the root and the aerial parts of Hierochloe odorata L. var. pubescens Kryl. growing in the east of China were examined by a combination of GC, GC-MS and HPLC techniques. A total of 169 volatile compounds were identified. This volatile oil was rich in coumarin, which accounted for 10.3 % of the root oil and 24.9% of the aerial part oil. Quantitative analysis by HPLC showed that ethanol extract of the roots to contain 3.57% (m/m) of coumarin and that of the aerial parts 3.72% (m/m).