Abstract: Although high frequency of regeneration system determines the transfer of foreign gene, it is different from transformation system. In order to increasing the regenerating frequency of carrot by Agrobacterium transformation, the concentration of plant growth regulators and selective agents were studied on the regeneration of hypocotyls from 2 cultivars, which were transformed with Agrobacterium tumefaciens containing recombinant human interleukin-2 gene (IL-2). The results showed that the carrot of different genotypes responded differently with the plant growth regulators. There was no significant difference on the three kinds of callus inducing medium for cultivar Linfeng. In contrast, the rate of embryogenic callus and the number of resistant plants in cultivar Japanese black filed five inch was raised with increasing plant growth regulator concentration. The highest rate of embryogenic callus was 87.5% on the medium containing MS+1.0 mg/L 2,4-D+1.0 mg/L6-BA+PPT, and the number of the resistant plants was 59. Therefore, it is essential to re-optimize the inducing medium with co-cultivation．