Abstract: Bioretention is one of the effective measures to control urban non-point source pollutions. A synthetic analysis of its structure, hydrologic effects, purification mechanisms and influence factors was presented. Bioretention can mitigate the stormwater and peak flow volume. It can effectively reduce the concentration of total suspended solids, particulate matter, heavy metals, organic pollutants and pathogens in stormwater runoff, but the removal of nitrate nitrogen and dissolved phosphorus is not stable. Bioretention facilities remove pollutants mainly through precipitation, filtration, adsorption, ion exchange, plant absorption and biodegradation. The removal of pollutants and reduction of stormwater volume are influenced by plant species, filler composition, depth, hydraulic conductivity and carbon addition. A long drying period will increase the nitrate concentration and setting internal water storage can reduce nitrate concentration. The structural design, operation and maintenance need to be further studied and optimized.