Abstract: Based on the 27-hour continuous investigations in August 2017 in the Humen outlet of the Pearl River Estuary, this study aimed to examine the characteristics and risks of heavy metals in suspended particulate matter, and thus to provide a scientific basis for the pollution prevention of heavy metals,. Field samples of suspended particulate matter (N=81) were collected, and the contents of six heavy metal elements, namely Zn, Cu, Ni, Mn, Pb and Cr were measured in lab. In this study, Pearson correlation analysis, factor analysis and potential ecological risk assessment index were introduced to analyze the characteristics, sources, and pollution risks of heavy metals in suspended particulate matter. The findings showed that the averaged contents of six heavy metals exhibited a clear decreasing trend as Mn, Zn, Cu, Cr, Pb and Ni, and their contents have a significant positive correlation with the concentrations of suspended particulate matter. The source analyses demonstrated that Cu, Zn, and Mn were mainly originated from mining industry and metallurgical plants from the North river, while Ni, Pb, and Cr were mainly originated from manufacturing industry such as batteries near the Humen outlet. In addition, the overall potential ecological risk was classified at a low risk level based on the results of potential ecological risk assessment. Moreover, Cu and Pb contributed the most to the ecological risks, the combined contribution rate accounting for >80%. Therefore, Cu and Pb were the main pollution controls, which should be paid more attention for safety.