[Objective] The aim was to introduce T-DNA into watermelon for its molecular marker research. [Method] Based on the method of foreign DNA introduced to Arabidopsis thaliana via dipping flowers, the stigma smear was used to transfer T-DNA into watermelon and its molec- ular marker research was carried out. [Result] The ideal transformed species was ZXG01078 for the highest fruit setting rate and the most devi- ant seedlings. The best concentration of kanamycin for treating watermelon seeds was 500-700 mg/L with differences among the species. The best position was spire leaf or young leaf and the best concentration of kanamycin for treating the watermelon leaf was 4 000 -8 000 mg/L with no significant difference among species. The steadily variation appearing of growing pointless and conjoined twin seedlings indicated that the nor- mal growth had been interiered by foreign DNA in the progeny. [Conclusion] This study had provided basis for the further research on watermelon.