The content of the heavy metals lead, copper, chromium, manganese, zinc and arsenic in Yangzonghai surface sediment was determined, the pollution level of heavy metal was evaluated by adopting geo-accumulation index method, and the source of the heavy metal in sediment was studied through principal component analysis. The results indicate that the mean values of lead, copper, chromium, manganese, zinc and arsenic in the surface sediment of Yangzonghai were 40.3, 97.6, 145.8, 617.9, 149.2, 31.4mg·kg-1 respectively. The accumulation of copper was the most serious, with the Igeo value reaching 2.42. The accumulation of lead was least serious, which was in mild pollution level. Heavy metals in the descending order of their pollution levels were copper, arsenic, chromium, zinc, manganese and lead. The principal component analysis indicates that the contribution rates of the first three principal components were 44.858%, 30.887% and 13.141% respectively, and the pollutants under high load were (lead, zinc, arsenic), (copper, manganese) and (chromium) in sequence. Industrial pollution and geochemical processes were the two main sources of heavy metals in sediment.