Abstract:Three plots of wheat were inoculated with different amount of wheat stripe rust pathogens, with the disease spread, 25 plots were infected with different levels of the pathogens. Canopy reflectance of wheat in different times were measured with an ASD field spectral handheld sensor, meanwhile the DI (disease index) was also investigated. Results show that wheat stands with different disease levels indicated different reflection curves. We found that with the DI increase, canopy reflectance between 600-703nm decrease distinctively, and with the DI increase, canopy reflectance between 770-930nm increase distinctively. So we built three regression models among DI and canopy reflectance at 650nm, 850nm wave band: at jointing stage, DI=13.03×R650nm-0.67×R850nm+10.22(R2=0.6570),at filling stage, DI=48.63×R650nm-2.41×R850nm-41.51(R2=0.8196),at milky stage, DI=24.42×R650nm-5.10×R850nm+67.77(R2=0.7336).