UF and NF are still researched variously as a pretreatment process of reverse osmosis membrane process. In this study, UF module was reviewed of the validity for configuration of UF combined with RO process to treat the landfill leachate. To improve of the risks followed while pretreatment of sand filter process, UF membrane was being used with vortex generating type, and it manufactured by polyester sulfone material. In order to obtain optimum flux from vortex generating type of membrane module process as a pretreatment of the RO process, the influence of operating pressure and fouling was examined. The consequence of UF membrane pretreatment process, more than 99% of SS removed optimized optimized operating pressure of 2 kg/cm² was the most suitable condition, the highest flux condition was selected with 85% recovery rate.