In order to study the composition and weathering of the ancient artificial silicate bead, the super depth of field microscopy, scanning electron microscopy and energy spectrum(SEM-EDS) and micro-Raman were carried out on a silicate bead unearthed from the M21 graveyard in Ma-Jia-Yuan to obtaining its apparent appearance, elemental composition and phase composition. The results revealed that its main component is Chinese Blue which mixed impurities like BaSO₄, PbCO₃, Pb₅Si₄O₈(OH)₁₀ and Cu₂Pb₅(SO₄)₃(CO₃)(OH)₆. So the silicate bead appears as light blue particles. It's produced by solid-phase sintering, and the weathering layer is composed of Pb₈O₅(OH)₂Cl₄. The article expounds on the technological development of Chinese Blue and the cause of the formation of alkaline lead compounds by weathering. The element analysis of the silicate bead shows that the content of Si is the highest, the content of Cu and Ba is roughly the same, and the content of Pb is lower, which may indicate that the firing of the copper barium silicate bead has begun to control the proportion of raw materials deliberately. Alkaline lead compounds should be formed in the process of burial. The oxides produced in the process of firing silicate beads at high temperatures did not react completely, and then they were buried underground and hydrated with alkaline soil water to form alkaline lead compounds. This article provides references for the research of ancient Faience products and copper barium silicate products and promotes the in-depth study of the history of science and technology in ancient China.