Nitrogen is one of the important indices for evaluation of crop growth and output quality. Spectral reflectance of leaves and concurrent leaf nitrogen content parameters of samples were acquired in maize test. The top 10 different vegetation indices were chosen after ranking with VIP as the independent variable for estimating nitrogen content of leaf in maize. The leaf nitrogen content (LNC) estimation model with different vegetation indices can be built using the integrated model of variable importance projection (VIP) — partial least squares (PLS). The optimal model was selected by using Akaike's Information Criterion (AIC). The optimal model was validated by leave one out cross-validation (LOOCV) method. The decision coefficient (R²), root-mean-square error (RMSE) and relative error (RE) of the optimal model respectively were 0.73, 0.16 and 0; R², RMSE and RE of maize by validating were 0.73, 0.19 and 0, respectively.