Abstract: The study aims on the effects of nitrogen application time and light quality (Red/Far red, R/FR) on the plant morphology and yield components of maize, and has significance for discussing the response mechanism of the growth and yield of maize under high density.‘Zhengdan 958’and‘Ludan 981’were used as materials, under the pot-cultivated basal fertilizer and dressing, artificial adding far red light LED lamp was used to set low R/FR ratio light environments, the response of maize growth physiological characters and yield to low R/FR was studied. Under low R/FR, plant height, total leaf area, specific leaf weight increased to different extents, while total leaf number remained the same as that of CK. Low R/FR treatment decreased SPAD of leaves but increased leaf net photosynthesis rate. Low R/FR treatment ultimately improved kernel numbers per row of maize ears, ear kernel weight and ear weight, but decreased the weight of ear axis, and the change of 1000 kernel weight was not significant in statistics. Low R/FR × cultivar interactions, low R/FR × nitrogen application time, the interactions of every agronomic character of the above treatments were not statistically significant. Low R/FR ratio could improve the ear kernel weight by increasing kernel number per row.