Hemp (Cannabis sativa L.) is a special economic crop and widely used in many field. It is significative for the government to master the information about planting acreage and spatial distribution of hemp for hemp industrial policy decision in China. Remote sensing offers a potential way of monitoring large area for the cultivation of hemp. However, very little study on the spectral properties of hemp is available in the scientific literature. In the present study, the spectral reflectance characteristics of hemp canopy were systematically analyzed based on the spectral data acquired with ASD FieldSpec portable spectrometer. The wavebands and its spectral resolution for discriminating hemp from other plants were identified using difference analysis. The major differences in canopy reflectance of hemp and other plants were observed near 530, 552, 734, 992, 1 213, 1 580 and 2 199 nm, and the maximal difference is near 734 nm. The spectral resolution should be 30 nm or less in visible and near infrared regions, and 50nm or less in middle infrared regions.