Genetic characters of Y09AB were analyzed using genic male sterile line Y09AB and Pol CMS maintainer 11217 and restorer 11354 in Brassica napus. Sterile plants in Y09AB were selected to be crossed with 11217 and 11354, and all plants in the F1 generation of the two combinations were fertile. The separation ratio between fertile and sterile plants in F2 generation was consistent with 15∶1, indicating that the fertility of Y09AB was controlled by 2 pairs of recessive nuclear genes and was not affected by cytoplasm. Y09AB was cross-positive and negative with another two recessive genic male sterile two-type lines 104AB and Xiangyou 402AB, and all the plants in F1 generation were fertile, indicating that the male sterile genes of Y09AB and the male sterile genes of 104AB and Xiangyou 402AB were non-allelic. Using 20 Brassica napus strains with different genetic background testcross with Y09AB to investigate the sterility of hybrid F1 generation and to analyze heterosis of hybrid combinations,we found that all the plants in F1 generation were fertile, and the recovery rate was 100%, which meant that Y09AB possessed complete and stable sterility, and had extensive source of recovery. The results of the combination identification test showed that among the 20 testcross combinations, 18 of them the yield was higher than the control variety, among which 7 of them increased the yield by more than 15%. There were 10 combinations in which the mid-parent heterosis was more than 25%, and 2 combinations in which the heterobeltiosis was more than 30%. The results showed that 7 of the 10 testcross combinations increased the yield than the control variety, and 3 of them increased the yield by more than 5%, with a maximum increase of 8.61%. The results of combination identification test and combination comparison test showed that Y09AB had high combining ability and strong heterosis potential, and was a recessive genic male sterile two-type line with great potential for development.