In urban backfilled soil, rainwater runoff can carry pollutants, causing water pollution issues. To understand this, simulated rainfall was used to study how nutrients and runoff move through different paths in the soil. In the beginning, surface runoff flow increases quickly and stabilizes, while subsurface runoff flow remains constant. The majority of pollutants, like solids, phosphorus, and nitrogen, are carried in surface runoff, leading to water pollution. This study's findings can help manage runoff pollution in urban backfilled soil systems.