Carbon and nitrogen metabolism of plants reflect the physiological status and growth vigor, which is the physiological basis of peanut yield and quality formation. Therefore monitoring the ratio of sugar to nitrogen in real-times important for growth diagnosis and nitrogen management for peanut plant. The main purpose of this study was to establish a quantitative model for monitoring the ratio of sugar to nitrogen in peanut leaves, through analyzing the relationship between the ratio of sugar to nitrogen and the canopy hyper-spectral parameters. The experiment was carried out on peanut variety NO.1. Different nitrogen level treatments were applied, and canopy hyper-spectral parameters were collected in different growth stages of peanut. Then the regression model of canopy hyper-spectral parameters and leaf ration of sugar to nitrogen was established The results showed that peanut leaf sugar to nitrogen ratio was in the dynamic change pattern of “high-low-high-low” within the growth process. And from seedling to pod, peanut leaf sugar to nitrogen ratio for all N treatment group was lower than the control group, and in the peanut harvest period N treatment, it was the opposite. The most suitable period for monitoring hyper-spectral parameter of leaf sugar to nitrogen ratio is seedling stage to full fruit maturity stage. Flowering and knit stitch stages vegetation index and the ratio of sugar to nitrogen correlation reached a significant level, and in these two stages, the regression equation established by DVI was more reliable. The R2 value of it was 0.866~0.993, and SE value was 0.026~0.083. After the peanut pod, using the EVI to establish regression equation is more reliable. The R2 value was 0.893~0.927, and SE value is 0.054~0.082. It is found that the characteristics DVI and EVI have the best performance, which could be used to monitor the ratio of sugar to nitrogen in the early and late growth stages reliably.