Abstract: Mining different resistant genes is the basis for the genetic improvement of crops durable resistance. Two radish (Raphanus sativus L.) inbred lines resistant to black rot (Xanthamonas campestris pv. campestris) (KB10Q-22, KB10Q-24) and one susceptible inbred line (KB10Q-33) were used to construct F2 populations. Black rot pathogen Xcc8004 were used to inoculate seedlings by leaf-cutting spray method to identify the disease-resistance. The genetic characteristics of resistance to black rot were studied with a mixed model of major genes plus poly-gene using P1, P2, F1, F2 populations. The results showed that the inheritance of the resistance of the above two resistant lines to black rot was different. The plants of F1 generation from KB10Q-22 expressed resistant. Its genetic model was mixed two major genes with additive-dominance-epistatic effects plus poly genes with additive-dominance-epistatic effects ( E_0 model) , while the plants of F1 generation from KB10Q-24 expressed susceptible , and its genetic model was mixed one major gene with additive-dominance effects plus poly genes with additive-dominance-epistatic effects (D_0 model). Major gene heritability for the two crosses were 87.73% and 55.64%, respectively. The heritability was mainly dominated by major genes.