Abstract: With the development of socio-economy in China, the proportion of urban initial rainwater pollution load in urban river pollution is increasing. To solve this problem, the purification effects of infiltrative dams on urban initial rainwater were investigated through pilot-scale experiment and simulation. The results showed that the infiltrative dams systems which used zeolite, limestone, sponge iron, and volcanic rocks as reactive media, had higher removal ratios of COD_Cr, SS, NH_4^+-N, TN, and TP, which was 84.69%, 89.65%, 25.66%, 24.46%, and 50.06%, respectively. Physical interception and chemisorption of fillers and sponge iron internal electrolysis were the main mechanisms for pollutant removal in infiltrative dams system.