Seven compounds were isolated from the traditional Chinese Medicine Qianhu, roots of Peucedanum praeruptorum Dunn. Their structures were identified as psoralen (II), 5-methoxypsoralen (III), 8-methoxypsoralen (IV), pteryxin (V), peucedanocoumarin II (VI), beta-sitosterol (VII) and qianhucoumarin A (VIII) by physico-chemical constants and spectral analyses (UV, IR, 1HNMR, 13CNMR, EIMS). VIII is a new compound with the structure of 3'(R)-hydroxy-4'(R)-tigloyloxy-3',4'-dihydroseslin. Its absolute configurations were determined by chemical correlation with known compounds. II, III, IV and VII were first isolated from this plant.