Fiber optic reflectance spectroscopy (FORS) is a nondestructive pigment identification method, so it is suitable for research on delicate and precious polychrome objects. The use of FORS has developed quickly internationally for research on cultural relics, but it is seldom applied in China because of the lack of a database. In our study, we investigated the effects of pigment granularity and provenance on reflectance spectra, summarized the reflectance spectral characteristics of blue, green, red and yellow pigments and used these characteristics to identify the pigments in architectural paintings and Chinese paintings at the Palace Museum. The results indicate that FORS is a quick and effective nondestructive pigment identification method.