In order to solve the problems that the exiting technologies do not adapt to the deterioration of the water quality in the water plant, the ultrafiltration was used to treat water respectively from ozonebiological activated carbon pool (process 1), sand filtration pool (process 2) and sedimentation tank (process 3) in the region of river network of southern China.It is found that the average DOC removal rate were 33.08%, 23.60%, and 18.55%, and the average alga removal are 98.71%, 97.84%, and 98.13% in the process 1, process2 and process3, respectively.The turbidity of the effluent is lower than 0.1 NTU, and the particles with their size bigger than 2 μm were lower than 20 per milliliter in all the three process.The transmembrane pressure increased by 6.59% and the water production rate of the UF membrane was 98.02% during 45 days pilot experiment in the process 1.When 0.65mg/L chlorine was added before ultrafiltration membrane, the transmembrane pressure was recovered effectively after hydraulic flush.And the transmembrane pressure increased by 2.91% and the water production rate of the UF membrane was 97.63% during 10 days pilot experiment in the process 2.The transmembrane pressure increased by 13.52% and the water production rate of the UF membrane was 97.01% during 20 days pilot experiment in the process 3.