An Agrobacteriummediated transformation system,using transient and stable transformation assays,was used to evaluate some factors influencing transformation in cauliflower.These included the precultivation time,the bacterial density,the inoculation duration time with Agrobacterium tumefaciens,the concentration of acetosyringone,the delay selection and the concentration of kanamycin in selection.Using cotyledons with 12mm petioles as explants,the best transformation parameters were:twoday precultivation,OD6000.30.4 of bacterial density,eightminute infection with Agrobacterium tumefaciens,twoday cocultivation,100μmol/L acetosyringone in the cocultivaiton medium and sevenday delay selection in kanamycin of 5mg/L.By optimizing the parameters on the procedure of Agrobacteriummediated transformation,a high transformation efficiency(35.7%)was demonstrated.The GUS transient expression could be an important indicator for cauliflower transformation.The development of an efficient Agrobacteriummediated transformation system opens up new opportunities for the functional characterization of genes and promotes the development of novel germplasm of Brassica vegetable genus.