This investigation was undertaken at the Experimental Farm of the Faculty of Agriculture, Moshtohor, Benha University during the two summer growing seasons of 2018 and 2019. To estimate combining ability under two nitrogen levels and superiority% relative two check hybrids for fivequantitative characters. N levels and genotypes mean squares were significant for all studied traits. Mean squares due to genotypes x N levels were significant obtained for all studied traits.SCA was higher than GCA for all studied traits revealing that the non-additive effects were controlled these traits. The overall study of GCA effects suggested that parentsM65, M66 and M48 were significant for general combiner for grain yield, M70 and M57 for earliness and M50 and M70 for short plants and ear stature. However, the genotypesM65xM10, M17xM10, M37xM10 and M48xCLM550 showed high SCA effect for grain yield plant^-1. The maximum heterosis was recorded by the crossM48xCLM550 in combined across nitrogen levelsthey out-yieldedSC128 and SC2031reached 18.00 and 14.00%, respectively.100-grain weight were correlated significantly with grain yield with r values being 0.707^** in the combined analysis.Factor analysis for combined across N levels divided characters of maize into three factors accounted for 78.63% of the total variability. The first factor contributed by 39.14% included ear length, ear diameter, No. rows ear^-1, No. kernels row^-1, 100-kernel weight and shelling%. The second factor accounted for 24.83% and is mainly loaded by days to 50% tasseling and silking. The third factor accounted for 14.66% is mainly described by plant and ear heights.