Abstract: The paper aims to measure the canopy hyperspectral reflectance and the content of chlorophyll a and b at the stage of budding, flowering and maturity under different nitrogen levels respectively and studied the relationship between the spectra and the content of chlorophyll, by taking the early maturing rapeseed variety ‘420’ as raw materials. The results showed that: under different nitrogen levels, all of the rape canopy reflectance spectra had the same trend, the parameters of chlorophyll content and spectrum showed a significant positive correlation between the vegetation index and coefficient of extraction, and the extracted vegetation index and the coefficient of determination from the fitted function model were also relatively high. There has a good prediction accuracy in this study which can be used as a reference for rapid and nondestructive remote sensing monitoring of quality breeding and regional scale growth of rape.