OBJECTIVE： To study the chemical constituents of ethanol extract from Cirtus aurantium. METHODS： The ethanol extract of C. aurantium was isolated and purified by silica gel column， open ODS column， preparation liquid chromatography， HW-40F gel column and macroporous resin column. The structure of compounds was analyzed and identified according to physicochemical properties and spectral data （mass spectrum， hydrogen spectrum， carbon spectrum）. RESULTS： Eight compounds were isolated from ethanol extract of C. aurantium， i.e. Rimboxo （1），Thymidine （2），Uracil （3），Cyclo-（Leu1-Ile2-Ala3-Thr4-Gly5-Thr6-Phe7） （4），Cyclo-（Leu1-Leu2-Pro3-Tyr4-Gly5-Ser6-Pro7） （5），Meranzin hydrate-β-D-glucoside （6），Umbelliferone （7），Linaloyl glucoside （8）. CONCLUSIONS： Compound 1， 2， 3， 8 are isolated from Citrus L. for the first time， compound 4， 5， 6 were isolated from C. aurantium for the first time. The study lays the foundation for quality evaluation of C. aurantium.