As a special kind of glazed ceramic, faience has an important role to play in the technological trajectory that eventually leads to the development of ancient glass. In China, faience products first emerged in early Western Zhou Dynasty (1046BC-771BC), and their great significance as well as brilliant colors varying between blue and green attracted a lot of scholars. However, scientific researches on the color source of Chinese faience in view of micro structure characterization are quite few. In the present work, analyses by energy dispersive X-ray fluorescence (EDXRF) and X-ray absorption near edge spectroscopy (XANES) were carried out on two faience beads with relatively blue and green color, respectively, both of which were excavated from Peng State archaeological cemetery site in Western Zhou Dynasty. The results show that the coloring element in both beads is copper with +2 valence, and the color divergence of these two beads may originate from different local chemical environments of Cu~(2+). It is suggested that the faience in this period is the earliest glaze with copper colorant in China.