Abstract: It was studied that the size of sample powders and instrumental resolution on tobacco nicotine NIR predictive model.The results showed that the powder size can affect largely the model.The model based on fine powders can gave more accurate evaluation indexes vs that based on rough powders.Therefore,it is suggested that the tobacco sample for spectra collection should be screened with a 0.441mm or below screen.The scanning sample at resolutions of 2,4,8,16,32 and 64cm-1 showed tat resolution could affect distinctively the model.The model based on higher resolution can give more accurate evaluation indexes vs that based on lower resolution.However,a resolution of 8cm-1 could gve satisfactory result,considering the scanning period and size of spectrogram file.