To isolate and identify the constituents absorbed into blood of rats after oral administration of citrus aurantium in Dachengqi Decotion(DT) based on the preliminary research of Serum Pharmacochemistry of DT. The isolation and purification of constituents were performed on silica gel column based on serum fingerprint profiles, their retention time and UV absorption spectra, and the structures of constituents were identified according to relative spectral data. The two kinds of constituents absorbed into blood from citrus aurantiumin in DT were identified as Naringenin and 1H-Pyrrole-2-carboxylic acid (Minaline). Both of them are the original ingredients from citrus aurantium. Serum pharmaco-chemistry was introduced to determine the bioactive constituents of Chinese medicine, and the constituents absorbed into blood after oral administration of citrus aurantium in DT were systematically isolated and identified.