In this paper, the model calculation is used to calculate the chemical species distribution of heavy metals in the Middle Yellow River. The results show that the pH value is the most important factor to control the distribution of each species, while the initial concentration of the heavy metals and content of suspended matter are other factors.In the Middle Yellow River, Cu and Pb mainly appear in sedimentary form, and Zn in adsorbed form. The content of free state heavy metal is very low. This study provides a scientific basis for forecasting the effect of heavy metal on environment for building the Xiao Lang Di reservoir.