Since the non point source is unspecified and estimating the degree of occurrence or identifying causing factors are difficult, it is not easy to control. Road runoff is considered a major source of pollution in developed urban sites. Road surfaces accumulate significant quantities of pollutants including nutrients, heavy metals and polycyclic aromatic hydrocarbons(PAHs). Many studies have characterized the constituents of stormwater. These constituents include polycyclic aromatic hydrocarbons(PAHs). Urban non-point source pollutant reducing treatment System is a part of the road runoff treatment which expanded polypropylene(EPP) media with a large surface area to treating the first flush of stormwater from road in field. Urban non-point source pollutant reducing treatment System consist of a container, a total 8.89m2 volume(3.6m(L), 1.3m(W), 1.9m(H)) which is made up of two element; sedimentation chamber of storage tank and filter tank. Under the operating conditions with 0.55h hydraulic retention time(HRT) and a capable of treating a maximum road runoff of 9.5m3/hr, the mean residual total PAHs were 0.699~1.339 µg /L and the percentage mean removal values were 61.4~69.7%, respectively.