In order to investigate the response of nitrogen on the morphological indices of various organs in maize growth and development, and build a model that could simulate the morphological indicators of organs in maize, a field experiment was conducted with maize, and four nitrogen fertilization treatments were set with nitrogen content of 0kg/hm2(N1), 225kg/hm2(N2), 338kg/hm2(N3) and 450kg/hm2(N4), respectively. The changes of organ morphological indicators, including leaf length, leaf width, internode length, internode diameter and leaf sheath length at different growth stages of maize under different nitrogen application levels were investigated, and the simulation model of crop organ morphological structure was established. The results showed that nitrogen fertilizer treatments had significant effects on leaf length (P<0.01), while different leaf positions had extremely significant effects on leaf length (P<0.001). Nitrogen treatment had no significant effects on leaf width, internode length and stem diameter, among which, leaf sheath length had significant effects on each growth stage in 2020 (P<0.01).In addition, the effects of growth stage, nitrogen treatment and leaf position on leaf sheath length were not significant. A simulation model of maize organ scale was constructed, and the model parameters were calibrated and verified by using two years of experimental data. The model simulation efficiency (EF) was above 0.72.The root mean square error (RMSE) of leaf length and leaf width were 7.285cm and 1.200cm, respectively. The RMSE of node length, internode diameter and leaf sheath were 1.593cm, 0.171cm and 1.282cm, respectively. The mean absolute error (MAE) of leaf length and leaf width were 5.817cm and 0.708cm, respectively. The MAE of node length, internode diameter and leaf sheath were 1.111cm, 0.116cm and 0.923cm, respectively. The results showed that the model had good prediction and interpretation for the simulation of the developmental process of various organs in maize.