The corrosion products grown on the bronze earcup unearthed at Silibao site, Yunyang county, Chongqing were investigated by microscope and identified by Raman spectroscopy. The results are as follows: The corrosion products grown on the earcup are pyromorphite(lead phosphate chloride, Pb₅(PO₄)₃Cl), cerussite(PbCO₃), lead oxide(PbO), cuprite(Cu₂O), malachite(Cu₂CO₃(OH)₂) and azurite (Cu₃(CO₃)₂(OH)₂). And the corrosion products of lead from inner to outer are : lead oxide, cerussite and pyromorphite. It can be deduced through analysis that pyromorphite in the out layer of the patina was formed through the process Pb→PbO→PbCO₃→Pb₅(PO₄)₃Cl. Cerussite will transfer to pyromorphite when in the enviroment with ambient PH, higher phosphate levels and chloride.