Abstract: The combining ability and heritability of hybrid rice parents, were estimated to provide an important theoretic foundation for breeding of hybrid rice parents and combinations.Five indica sterile lines were crossed with five indica restoring lines by incomplete dialle cross design.The six main agronomic traits of their F1 were analyzed to estimate their combining ability and heritability of hybrid rice parents.The results showed that plant height, effective panicle, grain number per panicle, seed setting rate, 1000-grain weight and yield per plant were affected by the additive effect mainly.There was no significant corresponding relationship between general combining ability and specific combining ability of different characters of hybrid rice parents.The effect of the male parent on effective panicle, grain number per panicle, seed setting rate, 1000-grain weight and yield per plant was higher than that of the female parent, while the effect of the female parent on plant height was higher than that of the male parent.Narrow heritability of the six main agronomic traits was 1000-grain weight>plant height>seed setting rate>grain number per panicle>effective panicle> yield per plant.