Partition the anthropogenic component from heavy metal accumulations is significant for modeling heavy metal concentration processes caused by intensive human activities. This paper measured urban sprawl of Yixing city, China since 1949 and evaluated accumulations of Cd, Cu, Pb and Zn affect by urban sprawl. An approach, content partition, was developed to partition total contents of heavy metal into three components: tendency，background and residual. Results showed that during the past three decades, Yixing city has grown fast, with an average rate of 71ha per year. Heavy metal contents increased with city growing old, which suggested that heavy metal concentration process has been modified by urban sprawl. Content partition method could effectually explain the control facts of heavy metal accumulation under the rapid urbanization area. Tendency components of Cd, Cu, Pb and Zn counted 16.6、18.4、33.22 and 2.7 %to the total contents, respectively. The spatial patters of tendency components of Cd, Cu, Pb and Zn show clear decrease gradient in the direction of urban-rural. Background components were expressed quantitatively by multi-regression equations. Finally, Flux equations were estimated to show the spatial distribution pattern of accumulation flux, which is useful for modeling the heavy metal accumulation process on the impact of human activities.