Based on FVCOM (Finite-Volume Coastal Ocean Model), the Lagrangian particle tracking method and dye-tracking method are used to carry out numerical simulations on pollutant traceability and early warning of the Qianshan River in Zhuhai. Experiments were carried out under idealized conditions to simulate the influence of various combinations of tide, wind, and flow on pollutant movement. The differences in drift path or diffusion rate were compared and analyzed. The results show that the tide, wind, and river flow all have significant influences on pollutant movement, especially the river flow. Strong river flow from upstream favors the discharge of pollutants. Pollutants released in deep water tend to stay in initial location longer and are harder to be diluted than those released in surface water. Wind direction plays a more dominant role in affecting the distribution of pollutants than wind speed does. The results of traceability experiments show that most of the traceability results are consistent with the pollutant release locations, and provide useful reference for further pollution control and research.