A method for preparing a purified beverage for renal failure patients and a purified beverage for renal failure patients prepared by the method comprises: introducing a raw beverage containing a high concentration of phosphorus or potassium into a filter unit such that the raw beverage flows through the inner side of the filter unit in a first direction and introducing a perfusion into the filter unit such that the perfusion flows through the outside of the filter unit in a second direction, and the raw beverage and the perfusion are circulating in opposite direction, whereby phosphorus or potassium in the raw beverage moves to the perfusion effectively, thereby preparing a purified beverage containing a low concentration of phosphorus or potassium.