As an important field in environmental science, the research on the locating issue of heavy metals pollutants source has increasingly attracted attention of scholars and society. In order to locate the pollutants source, we should firstly figure out the spatial distribution of heavy metals pollutants and pollution degree of different subareas in a limited area. Based on the datasheets from CUMCM 2011, we obtain the spatial distribution figures of heavy metals on MATLAB platform. Then, we introduce SFPI method to build an evaluation model of pollution degree in different subareas, with analyzing of the result of which, we can approximately conclude that the location of heavy metals pollutants source may be located in Industrial Area and Traffic Area. Further analyzing, to position the pollutants source more precisely, we introduce 2D convection-diffusion equation to describe the pollutant pathway of heavy metals, solve the equation with FDM algorithm on Maple platform, and obtain the propagation function of heavy metals concentration. Finally, we furtherly modify the propagation function and then figure out the precise coordinates of the pollution source and the corresponding subareas.