In this research, a up-flow filtration device was developed for the on-site treatment of urban stormwater runoff during storm events, and particle removal characteristic of porous polypropylene as a filter material was experimentally examined. The up-flow filtration device showed high removal efficiency, more than 90% (mainly 95-98%) of the SS concentration of influent particles. After the sedimentation in the bottom part of up-flow filtration device, the up-flow filtration filled with porous polypropylene material was able to remove more over 70% of the SS concentration in the up-flow. The increase rate of captured particle amount retained in 10, 20 cm from the bottom of filter bed was lower while flow rate increased. This is attributed to the fact that fine particles detached or not removed by the bottom of filter bed were mainly retained in that section. The particles (mainly finer particles) captures were increased by those particles (mainly large particles) retained in the initial stage for influent particles. However, the improvement of particle removal efficiency (as SS concentration) was not observed along with this phenomenon. The reason may relate to the fact that the particles retained by the captured particles in the initial stage were fine particles.