Abstract: Spectral information of surface object is the base of multispectral remote sensing. Characteristics of spectral information reflect the existence, change and difference of the objects. As a part of the research of physical properties of granite, we analyze the reflective spectral features of two types of Early paleozoic granite in Guangdong province. The samples of the I-type granite are from longtang rock mass in central Guangdong and the S-type granite from Yunkai mountain in western Guangdong province. Through PIS-B high accurate instantaneous spectrometer, the reflecive spectral properties of two granites were obtained. The brightness difference between the two granites is very high. Spectral reflectance of S-type granite is greater than that of I-type granite. Furthermore, the differences of field reflective spectral properties between two granites and between the granites and surrounding rocks are analyzed, which provided a theoretical basis on which different type of rocks can be discriminated in the remote sensing images. In consequence, the techniques and methods to dispose the remote sensing images are also designed on the basis of known differences of spectral properties. Among the several possible designs, an ideal one is to composite the images of TM4(R), TM4/3(G) and TM2/1(B). On the composite images, two granites and the surrounding rocks can be easily discriminated.