Ten yellow maize inbred lines were derived from different sources were evaluated in this study to estimate combining ability, type of gene action and superiority % of the F1 , s over commercial check hybrids. In 2019 grown season, all possible combinations between these lines were done in a half diallel (Griffing's 1956, method 4, model 1) to give 45 crosses at Sids Agricultural Research Station. In 2020 season, 45 crosses along two commercial hybrids; SC. 168 and SC. 3444 were evaluated in replicated trails conducted at three locations; Sakha, Sids and Nubaria Agricultural Research Stations. Data were recorded for days to 50% silking, plant height, ear height, ear position%, late wilt resistant % and grain yield. The results showed significant differences between the three locations for all the studied traits except LWR % and GY traits, indicating that the three locations differed in the environmental conditions. Mean squares of genotypes and their interactions with locations were significant or highly significant for all the studied traits. The results showed that the general combining ability and specific combining ability variances were significant or highly significant for all the studied traits, indicating that both additive and non-additive gene action were important in the inheritance of these traits. The parental lines Sd. 3180 and Sd. 21 had a good GCA effects for all the studied traits. The crosses Sk. 1 x Sd. 15 and Gm. 6052 x Gz. 658 showed desirable values of SCA effects and superiority% over check for yield.