Abstract: The optimum process of extracting fraxin, esculin and esculetin as active coumarin from Cortex fraxini(Qinpi) bark was studied. A rapid and simple method used to determine fraxin, esculin and esculetin in C. fraxini by capillary zone electrophoresis(CZE) was described. The effects of EtOH volume fraction, extracting times,extracting time,and ratio of material to liquor on extraction yield of 3 kinds of coumarin were investigated by orthogonal test. The optimum extracting conditions confirmed by the index of extraction yield of 3 kinds of coumarin were as follows:ratio of material to liquor 1:9(g:mL),three times of reflux extraction with 65% EtOH, each extraction 1h. The yield of total coumarin was 3.61%