Peucedanum is a genus of flowering plant in the carrot family, Apiaceae. The root of Peucedanum praeruptorum Dunn. was extracted with solvents at different polarity obtaining three chemical fractions: aqueous (H2O), n-butanol (BuOH) and ethyl acetate (AcOEt). From AcOEt praeruptorins A and B were isolated by column chromatography on silica gel, using toluene/ethyl acetate as eluent, and identified by 1H and 13C NMR analysis. A new angular dihydropyranocoumarin named qianhucoumarin H and four known coumarins, peucedanocoumarin I, 5,8-dimethoxypsoralen, isoscopoletin, umbelliferone along with anchoic acid were isolated from the root of Peucedanumpraeruptorum. By spectral analysis and chemical evidence, the structure of qianhucoumarin H was elucidated as 3′(S)-angeloyloxy-4′(R)-isovaleryloxy-3′,4′-dihydroseselin and the absolute configurations were established by chemical correlations with known compounds.