Belonging to the technical field of drinking water safety guarantee, the invention in particular relates to a seating-hanging dual-use water quality based water purifier and a use method. The water purifier comprises a double-flow switcher and a water diversion hose. The water purifier is characterized by also including a filter core cylinder A, a multi-magnetic core cylinder, a filter core cylinder B, a filter core cylinder C, a tee joint, and a drinking water metal pipe fitting, a connecting pipe fitting, a timer and a drinking water valve that are mounted on the external surface of a water purifier case. The water purifier realizes first level and second level water supply according to water quality through the double-flow switcher, and forms third level drinking water supply through the drinking water metal pipe fitting. The water purifier also has five user-friendly unique designs including filter core maintenance real-time reminding, seating-hanging dual-use and the like. The water purifier provided by the invention can effectively remove suspended matters, particles, rust and other impurities from water, activate water vitality, make tap water turn into weakly alkaline high-energy micro-cluster water, also can play a bacteriostatic and bactericidal role, and the purified water can be drank directly.