The chemical compositions of some representative silver coins and their corrosion products excavated from Qionglai city, Sichuan , were determined using analytical scanning electron microscopy as well as X ~ ray dif- fraction in order to decide how to protect them. The results show that these silver coins contain predominant Ag and reasonable Cu.and their corrosion products mainly contain predominantly Ag and some Cu ,and that their corrosion products are mainly Cu20.CuC03 . Cu( OH)2 and a little AgCl. Accordingly, ultrasonic vibration combined with 5% EDTA was used to remove the corrosion products. The coins were then sealed and packaged into specially made acrylic boxes. The analytical data provide useful information and an example for the preservation of silver cultural relics.