In order to explore the improvement effect of low-impact development(LID)measures on the urban rainwater-runoff-pollution process, we took an area in Guangzhou as the research object and proposed four LID reconstruction measures(green roof, bioretention cell, permeable pavement, combination of three LID), and the SWMM model was constructed to simulate and analyze the hydrological and water quality effects of the different LID reconstruction measures under the five rainstorm recurrence periods. The results show that: under the single LID, the permeable pavement effect is the best when the rainfall recurrence period is large. Under this scenario, the flood peak flow reduction rate, peak time delay and total flow reduction rate have reached the maximum; In addition, combination of three LID has the highest total flow reduction rate of 26. 12% ~ 34. 40%; Under a single LID, permeable pavement has the best effect on COD and NH₃-N concentration peak reduction and peak time delay; The combination of three LID have the highest reduction rates for COD and NH₃-N, Which is 50. 51%~ 60. 83% and 53. 16 %~ 58. 47%, respectively. The LID reconstruction measures have reduced urban flooding, COD and NH₃-N to varying degrees, and the combination of LID reconstruction measures has the best effect.