A strategy that ultrahigh performance liquid chromatography-quadrupole-exactive orbitrap high resolution mass spectrometry（UHPLC-Q-Exactive orbitrap HRMS） based untargeted metabolomics was developed in combined with chemometric automatic data analysis software（AntDAS-LCHRMS） to investigate the metabolites from four types of

E. ulmoides Oliv.

leaves processed by different drying treatments（

i. e.

，freeze drying，heat pump drying，oven drying，sun drying）. The data of samples was acquired by UHPLC-Q-Exactive orbitrap HRMS under both positive ionization mode and negative ionization mode，and directly imported into AntDAS-LCHRMS for automatic data analysis. The results indicated that about 71 differential metabolites were identified based on the above-mentioned data analysis workflow，and 40 compounds were further confirmed by standards，including iridoids，organic acids，flavonoids，amino acids，nucleosides，vitamins，sugars，lignans，and coumarins. Among of which 25 metabolites were identified and confirmed by standards under both positive and negative mode，including asperuloside，chlorogenic acid，rutin，isoquercitrin，asperulosidic acid and geniposide，etc. Finally，hierarchical clustering analysis（HCA），principal component analysis（PCA），and heatmap analysis were used for discriminating samples from various drying treatments. The results showed that

Eucommiae Folium

obtained from different drying treatments could be clearly separated，and compounds of them were significantly different. Heatmap analysis further explicated the compound variations in

E. ulmoides Oliv.

leaves from different drying groups. Samples of sun drying had higher levels of amino acids such as phenylalanine and tryptophan. Samples of freeze drying and heat pump drying had higher levels in organic acids，iridoids，and sugars. Samples of oven drying had higher levels of nucleotides and flavonoids. The content of flavonoids differed little among freeze drying，heat pump drying，and sun drying. The results could be helpful to offer a scientific guidance for the quality evaluation and application of

E. ulmoides Oliv.

leaves processed by different drying treatments. In addition，the developed strategy provides a new candidate for the analysis of other complex medicinal plant.