To understand the formation of corrosion on a Western Zhou Dynasty bronze excavated from tomb M24 in Ouhai, Zhejiang province, scanning electron microscopy (SEM), Xray fluorescence spectroscopy (XRF), Xray diffraction (XRD), high performance ion chromatography(HPIC) and other instruments were used to analyze the corrosion products of the bronze sword and the soil around its burial site. The results show that the bronze sward is severely corroded. Copper has been lost and the major corrosion products are Sn compounds. By measuring corrosion potential and determining the potential-pH of the CuH₂O system the progress of corrosion of this bronze can be deduced. These results will provide useful information for similar relics.