In order to make use of the heterosis in hybridization breeding, it is of great significance to explore excellent germplasm resources and analyze the combining ability. By deployment of 8 restorer lines and 21 sterile lines, which served as male and female parent, respectively, this study generated 168 hybrids following the incomplete diallel hybridization 8×21 (NCII). These materials were analyzed for the combining ability and the genetic parameters of 8 agronomic traits. The results showed that the effective panicle number, panicle length and 1000-grain weight were mainly affected by the additive effect, and the plant height, filled grain number and the seed setting rate were mainly affected by the interaction of non-additive effect. The plant height, effective panicle number, spike length, 1000-grain weight and yield per plant of hybrid combination were largely female-dependent, while the total grain number was largely male-dependent. The grain number and seed setting rate were genetically contributed by both parents. The effective panicle number and yield per plant were depending on the interaction between genetic components and environment conditions. The parents with combining ability were 843A, Yixiang 1A, Huhan7A, Changhui 871, Changhui T025 and Yazhan. Out of these genotypes, Yixiang 1A and Changhui T025 exhibited the best General Combining Ability (GCA) effect value. The hybrid combination Yixiang 1A/ Changxianghui 1 exhibited the excellence on Special Combining Ability (SCA), and the hybrids including Yixiang 1A/ Changxianghui 1, Qianxiang 059A/ Changhui 121, Guang8A/Changhui 881 were qualified. Thus, by investigating the combining ability of main agronomic characters in restorer lines, this study provided some scientific basis for the breeding of hybrid rice restorer lines.