The corrosion products on the silver and copper coins displayed in the China Numismatic Museum were analyzed by 3-D video microscopy, SEM-EDS, XRF and XRD. The materials of the scaleboard were characterized by FTIR, and the origin of sulfide was explored. The corrosion product on the silver coins was acanthite (silver sulfide), while the corrosion product on the copper coins included copper sulfides and oxides. Analytical studies suggest that the neoprene adhesive used on the display case my decompose and release H2S under condition of high temperature and humidity, and that the reaction of H2S with silver and copper coins resulted in the corrosion products.