The major objective of this study was to understand the effects of ecological bag mulching on soiland water conservation on the loose media slopes in quarries.Based on the observed runoff data in ten rainfallevents in 2011,the authors studied the changes of runoff and sediment yields under three rainfall intensitiesand four types of slopes with mulching of ecological bags in the experimental plots,located in ZhoukoudianCounty of Fangshan District.It was found that ecological bag mulching reduced significantly water losses andsoil erosion;with the different rainfall intensity and slope,the observed runoff depth and sediment yield ofthe plots with ecological bag mulching were 23.5%～25.2%and 53.1%～60.6%lower than that of the control plot,respectively.The effects of reducing runoff and soil loss were most notable with a rainfall intensityof 12.05mm/h and slope of 35°.The regression analysis indicated that runoff and sediment yield correlatedclosely with rainfall intensity and slope in general,while no corresponding relation were found between runoff depth and sediment yield in different rainfall intensity,vegetation and slope conditions.The mulchingtechnology with ecological bags was one of the important measures in controlling soil erosion.