Using 4(3)-quinazolinedione, the active constituent of "Daqingye", as the quality control criteria, 4 samples of the herbal drug collected from Isatis indigotica, Baphicacanthus cusia, Polygonum tinctorium and Clerodendron cyrtophyllum were comparetively analyzed by RP-HPLC. The results showed that the average 4(3)-quinazolinedione contents (microgram/g) were 30.7, 7.2, 4.4 and 27.5 respectively. This method was proved to be quick, simple and reproducible, and provided a reliable basis for the quality control and evaluation of Chinese Traditional Drug "Daqingye".