Kaineng commercial direct drinking machine provides two filtration processes, reverse osmosis and nanofiltration, respectively, to provide purified water and mineral water. The pure water type can filter bacteria, viruses, microorganisms and heavy metals. Nanofiltration type not only filters, but also retains some beneficial minerals and adopts four-stage filtration process and is equipped with over-flow ultraviolet sterilization device. This water purifier uses high filtration, high water to reflect the concept of environmental protection.