To investigate the removal mechanism of pollutants from urban rainfall runoff by permeable brick, ceramic brick, cement brick and steel slag brick were applied to study their decontamination performance. An adsorption experiment with granular materials obtained by crushing the bricks and a filtration experiment with complete bricks were carried out, and suspended solids (SS), chemical oxygen demand (COD), total organic carbon (TOC), dissolved organic carbon (DOC), ammonia nitrogen (NH₄⁺-N), total nitrogen (TN), total phosphorus (TP) and heavy metals (Cu, Zn and Pb) in the influent and effluent were measured. The results showed that (I) NH₄⁺-N, TN and COD dissolved out from most of the particulate materials during the adsorption process. (II) The filtration performance of permeable bricks for dissolved pollutants such as COD, NH₄⁺-N and TN was inferior to that for SS, TP and heavy metals. The soluble substances were difficult to intercept, and the release from the brick materials was the reason for the low removal rate. (III) The compact and dense pore distribution was conducive to the removal of organic carbon particles larger than 0.45 μm, and non-sintered bricks had higher DOC removal than the other bricks because of the flocculation of cement hydration products. The study could offer a new perspective for the decontamination of permeable bricks.