The invention provides an air purifier and solves the problem of reduced purifying efficiency due to long-term use and the problem about air disinfection in the technical field of air purification. The air purifier is characterized in that the structure is simple, the air purifying efficiency cannot be affected after long-term use and various bacteria in air can be killed by adding a disinfecting solution, a switch (B) in an attached drawing 4 and a blast volume controller are rotated to the position 1 or 2 and rotated to send signals to a circuit board (H), a turbo-blower (D) and a water pump (K) are started simultaneously for operation by the circuit board (H), the water pump (K) conveys water to a sprinkler head (J), and water is sprayed to outside of a diversion trench. The turbo-blower (D) exhausts air in a box to an air outlet (A). Specifically, the air flows into an air diversion trench (F) from an air inlet fly net (G) in an attached drawing 2, is cleaned by the sprinkler head (J), flows through a water spray blocking net (E) in an attached drawing 3, enters a turbo-blower air inlet (C) and is exhausted from the air outlet (A).