The invention belongs to a micromist humidification discharge water recycling device of a central air conditioner. The device comprises a discharge water collecting pipe, a settling tank, a rough filter tank, a water tank, a first-grade pump, a water purifier, a second-grade constant-pressure pump, a clear water tank and a clear water outlet pipe serially connected in sequence. The device further comprises a water replenishing pipe; the water replenishing pipe is connected with the water tank; a water inlet end of the water replenishing pipe is positioned in the water tank; and a floating ball valve is arranged at the water inlet end of the water replenishing pipe. The device is simple in structure, low in cost and high in automation degree, and can fully recycle the micromist humidification discharge water of the central air conditioner.