A gradient HPLC-DAD-ESI MS method has been developed for simultaneous determination of multiple bioactive compounds such as abietane-type diterpenes, flavonolignans and phenolic compounds in compound preparations of Silybum marianum and Salvia miltiorrhiza. The separation was completed on an ODS column using 0.5% (v/v) formic acid aqueous solution and methanol as gradient mobiles. Fourteen components can be identified by ESI MS working on ESI(-) and ESI(+) switching mode, respectively. Ten components can be quantified by using external standard method with UV detecting at 254 and 280 nm, respectively. The correlation coefficients of all the calibration curves were found to be higher than 0.992. The recoveries of the standards were about 96-101%. Besides quantification of the components, the chromatograms acquired by this method can be used as the bioactive components fingerprints for the quality control of compound preparations of S. marianum and S. miltiorrhiza.