Abstract:The plant growth retardant triadimefon was used in culture by shoot apex of Brassica campestris ssp. chinensis var. utills. Triadimefon at low concentration (1- 5 umol/L) increased the propagation coefficient of shoot and leaf number, decreased shoot vitrification, and improved the growth of seedlings. It was also found that the rooting ratio was increased with increasing concentration of triadimefon in the medium. It is suggested that triadimefon may be used as a good plant growth regulator in rapid multiplication of Brassica campestris ssp. chinensis var. utilis.