Six major summer maize cultivars, including ZD958, XY335, ZD309, AY3111, XD20 and DK653, were selected as experimental materials, and five N application of 0, 120(reducing 1/2 of normal N rate), 160(reducing 1/3), 200(reducing 1/6) and 240 kg/ha(normal N rate) were setup. The grain yield, the transformation of N after anthesis, chlorophyll fluorescence characteristics and NR and GS activity of leaf in the grain filling stage were compared. Compared with no nitrogen application, the grain yield with adding N fertilization was increased by 20.0%, but no significant differences were obtained in grain yield, N concentration, HI and NHI among normal N rate, reducing N 1/3 and 1/6. ZD309 and XY335 showed higher yield and NHI than other genotypes. The transformation amount of leaf in ZD958, XY335 and ZD309 was increased with the increase of N application level, but N remobilization efficiency of stem under the adding N treatments had no significant difference among the six cultivars. Higher chlorophyll Fm, PI and NR activity, and similar SPAD of leaf in the grain filling stage were found under the reducing 1/3 and 1/6 normal N, compared with normal N rate treatment. The maximum SPAD and PI of the leaf after anthesis were AY311. NR and GS activities of leaf in ZD958, XY335 and ZD309 were significantly higher than the other three genotypes.