Abstract： Analysis of the combining ability and the inheritability of 5 indexes of resistance to leaf blast during seedling stage of hybrid rice was conducted with a set of 7×7 incomplete diallel crosses. The results as follow:(1) The resistance, which had a great inheritability, was controlled by both additive heredity and non-additive heredity,but the former was more important than the later.(2) Restorer's GCA was more important than CMS line's,but the later had significant effect on the resistance of its crosses.(3) K42A、K40A、Duohui No.1 and Chenghui 149 had better GCA of resistance to leaf blast than the other tested parents.So in the hybrid rice breeding for resistance to leaf blast,the evaluation of parent's GCA and the selection of restorer with great GCA were very important,but the assession of crosses' resistance and CMS line's controbution to its crosses shouldn't be ignored,and 2 CMS lines(K42A、K40A) and 2 restorers(Duohui No.1、Chenghui 149) should be utilized as fine parents.