Abstract: Objective To study the chemical constitutes of the essential oil in the underground part of wild Houttuynia cordata Thunb in Dali. Methods GC-MS method was used to study the chemical constitutes of the essential oil. Results 24 constituents were isolated and identified（88.93% of the total essential oil），and the main compounds were capric acid，hexadecanoic acid and 2-undecanone. Conclusion There were significant differences between the essential oils in the underground of wild H.cordatain in Dali and those in other producing areas，which provided a scientific evidence to develop and utilize the essential oil existed in underground part of Houttuynia cordata Thunb.