The compositional changes of wormwood (Artemisia princeps var. orientalis) essential oils were studied under 4 different storage conditions i.e., being exposed to air at 20 and $40^{circ}C$. Sixty-four volatile compounds consisting of 24 terpene hydrocarbons, 18 alcohols, 11 ketones, 6 esters, 1 aldehyde, 2 hydrocarbons, and 2 oxides were identified on the basis of their mass spectra characteristics and retention indices in original wormwood essential oils. Identified compounds constituted 80.53% of the total peak area. Borneol (12.13%) was the most abundant compound, followed by $alpha$-thujone (8.66%), T-cadinol (6.67%), and 1,8-cineole (6.21%) in original wormwood essential oils. Under the condition of $40^{circ}C$ of temperature with the cap being opened for 3 min everyday respectively during 6 months of storage, the total amount of functional groups in essential oil determined by peak area percent were decreased by 79.45%, at most. The total level of monoterpene hydrocarbons decreased markedly in the aerobic condition and high temperatures. Whereas the total level of esters increased significantly. Wormwood essential oils were stored in experimental conditions, with the changes in the volatile compounds of essential oils being accelerated by high temperatures and contact with the atmosphere.