Abstract: In this report, study on molecular identification of Fusarium wilt resistance for diploid and tetraploid watermelon breeding lines using dCAPS marker “4451_fon” which published in 2013 was carried out. The results showed that all diploid lines and tetraploid lines except No.D16 and D17 were Fusarium wilt resistant genetype material, could be identified as having Fusarium wilt resistance, and the result was in accordance with artificial inoculation identification. Molecular identification results also showed that those resistant lines were homozygote, so Fusarium wilt resistant gene would not separate when lines self-crossed, and there was no necessary carry out single resistant plant selection in their progeny population. The final conclusion were that dCAPS Marker “4451_fon” could be applied to molecular marker assisted selection for Fusarium wilt resistance breeding in watermelon to increase breeding selection efficiency and enhance breeding progress.