The invention discloses a centrifugal fan air inflow dustproof cover. A ventilation air plate is arranged in a dustproof cover body. A dustproof plate is arranged above the ventilation air plate. A fan protective net is arranged at the upper end face of the dustproof cover body. Buckles are arranged on the periphery of the fan protective net. Fixed clamping seats are arranged on the periphery of the dustproof cover body. The positions of the fixed clamping seats correspond to those of the buckles. An installing screw is arranged in the circle center of the fan protective net. The ventilation air plate is provided with fan blades. The centrifugal fan air inflow dustproof cover is reasonable in structure, convenient to use and installed on a centrifugal fan to effectively prevent dust and foreign particles from entering the centrifugal fan, the relation between the yield strength and hardness of the fan blades is set reasonably, so that reliability of the fan blades during working is improved, and service life is prolonged. The inner condition of the fan blades is monitored in real time through a monitoring system, the fan blades are replaced in time before being damaged, and the conditions that the fan blades are damaged during working and equipment is damaged are avoided.