Based on the detection and analysis of the distribution characteristics of pyrene in shallow ground water in a waste metal dismantling site, pyrene contamination sources, pathways and pollution mechanism are explored. The results indicate that site center and site downstream 2 km contaminated clearly by pyrene in shallow groundwater. Controlled by local groundwater flow, pyrene migrates smaller distance vertically to groundwater flows, less than 0.5 km generally. Migration and transformation of pyrene in groundwater are also affected by factors such as pH, Eh and DO.