Abstract: Combined pilot-scale treatment process of high density settling tank and UF is applied to treat micro-polluted raw water with low-temperature,low-turbidity,high-algae,high-organic,et al.Experimental results show that combined process has excellent removal effects on turbidity,algae and microorganism index.The turbidity of UF membrane effluent is 0.07~0.09NTU,algae is removed completely,and Escherichia coli group is not detected.The average removal rate of COD_Mn and ammonia is 31.12% and 52.65% respectively.The removal rate of COD_Mn is improved to 38.6% and 44.6% respectively by addition of powered activated carbon with 3mg/L and 5mg/L refluxing in high density settling tank,and COD_Mn value of UF effluent is lower than 3.0mg/L.Membrane pollution can be lessened.It decreases the increasing rate of trans-membrane pressure drop.Chemical washing period of UF extends effectively.