Chlorophyll is the important factors of the crop in its growth stage, and it is the favorable indicator of nutrition stress and photosynthesis. Site-specific crop nutrition diagnosis is the basics of the scientific fertilizer management, and it is essential for the practice of precision agriculture. Spectral properties of the oilseed rape leaves in different nitrogenous fertilizer levels were measured using visible-near infrared reflectance spectroscopy (Vis-NIRS) with natural illumination in the present study. According to the unique spectral properties of the crop, multiple stepwise regression technique was used to find the relationships between chlorophyll content and red edge, green edge. The result shows that the model with two independent variables (red edge, green edge) was better than with the one independeot variable (red edge). The correlation coefficient was 0.863, 0.848, and SEC was 5.273, 5.459, respectively. It can be seen the combination of the red edge and green edge can accurately predict chlorophyll content.