Abstract:Leaf area index (LAI), aboveground fresh weight (AFW) and aboveground dry weight (ADW) are important parameters in monitoring of crop growth status. The tobacco stepwise regression models and characteristic variable were established by analysing the relationship between 17 spectral parameters and LAI, AFW, ADW in different type, breed, fertilizer treatments. The results showed that 5 regression equation R2 and coefficients reached 0.05 significant level. The first variable screened was Rg/Rr for the regression models of 17 spectral variables. The correlation coefficients of Rg/Rr and LAI, AFW, ADW were 0.759、0.611、0.647, respectively and that of R2 were 0.576、0.3727、0.4184. They all reached 0.01 significant level. So Rg/Rr was the characteristic variable of LAI, AFW, ADW. Also, RVI could been used to estimate LAI、ADW by using the regression equation of 8 vegetation indexes. Through testing, all the models had good estimate effects,and regression models of Rg/Rr were better than those of RVI. This study indicates that it is feasible to monitor the tobacco growth by the characteristic parameters of hyperspectra and broadband spectra, and we can choose effective models based on the data, providing method of analysing remote sensing data.