Based on the resistance identification of scab at seedling stage of cucumber, two materials resistant to Cladosporium cucumerinum (HX1, Cucumis sativus var. sativus, DI=5 and HX5, C. sativus var. xishuangbannesis, DI=38.7) and one susceptible material (HX8, C. sativus var. sativus, DI=80) were obtained. Six generations (P1, P2, F1, F2, B1 and B2) of two combinations (HX1×HX8, HX5×HX8) were used as genetic populations and resistance identification of scab at seedling stage were performed. The genetic characteristics of scab resistance were analyzed with a mixed model of major genes plus poly-gene. The results showed that the inheritance of scab resistance of above two gene sources was different. The plants of F1 generation of HX1×HX8 combination expressed resistant while those of HX5×HX8 combination showed to be susceptible. The inheritance of HX1 was fitted to a mix genetic model of two major genes with additive-dominance-epistatic effects plus poly-genes with additive-dominance effects (E_1 model) and that of HX5 was fitted to poly-gene（C）model. For high resistance material HX1, the additive effect of two major genes was both larger than dominant effect. Heritabilities of the major genes in F2, B1 and B2 were estimated to be 96.91%, 98.19% and 72.51% respectively. Poly-gene heritabilities of three generations were all 0. Major gene heritability was important in 3 generations. For resistance material HX5, the heritability was mainly dominant effect of poly-gene.