The petroleum ether fraction of ethanol extracts from Boenninghausenia sessilicarpawas isolated by combination of several chromatographic methods including silica gel, ODS, and Sephadex LH-20 column chromatography, and finally purified by preparative HPLC. The structures of the isolated compounds were identified based on the spectral data. As a result, 15 coumarin compounds were isolated and identified from the petroleum ether extraction. Their structures were determined as osthenon (1), murrangatin (2), 3-(1,1-dimethylallyl)-8-hydroxy-7-methoxycoumarin (3), xanthotoxin (4), isopimpinellin (5), chalepensin (6), isodemethylfuropinarine (7), imperatorin (8), phellopterin (9), heraclenol (10), byakangelicin (11), neobyakangelicol (12), chalepin (13), luvangetin (14), 3-(1, 1-dimethylallyl)-xanthyletin (15). Among them, compounds 1 - 3, 6 - 10 and 14 -15 were firstly isolated from B. sessilicarpa.