Centrifugal fan is a high efficiency, low speed, low noise centrifugal fan. It is made up of advanced aerodynamic impeller structure, logarithmic spiral casing, and has the characteristics of novel and compact structure, small vibration and convenient adjustment during use. It is used for air conditioning units, large and small hotels, restaurants, ventilation or fume extraction; it can also be used as a general purpose indoor and outdoor ventilation for general buildings. The medium to be transported is air or other unnatural, harmless gas to the human body, the medium does not contain viscous substances, the gas temperature is ≤80 °C, the dust and solid impurities ≤150mg air-conditioning fan is used in industrial and mining enterprises, hotels, large shopping malls, etc. The air-conditioning box and air-frame air-conditioning unit of various sizes and specifications of the facility are suitable for various sizes of air-conditioning boxes, wind-frame air-conditioning units, central air-conditioning units and various purification equipment for industrial and mining enterprises, hotels, large shopping malls and other building facilities. It has the characteristics of strong versatility, high efficiency, low noise and large air volume.