When the raw liquid flows through the surface of the membrane, the micropores densely covered on the surface of the ultrafiltration membrane allow only water and small molecules to pass through to become permeate, and the substance in the original solution having a volume larger than the micropore of the membrane surface is trapped on the liquid inlet side of the membrane. It becomes a concentrate, thus achieving the purpose of purifying, separating and concentrating the stock solution. There are about 6 billion 0.01 micron micropores on the wall of the ultrafiltration membrane per meter. The pore size only allows the passage of water molecules, beneficial minerals and trace elements in the water, and the smallest bacteria are more than 0.02 microns. Therefore, bacteria and colloids, rust, suspended matter, sediment, macromolecular organic matter, etc., which are much larger than bacteria, can be intercepted by the ultrafiltration membrane, thereby realizing the purification process.