The limited Value of specific A-weighted sound level in the present standard JB/TQh341-84 promulgated by the Ministry,which is applied to determine the unaccuracy of noise characteristics for axial-flow ven tilators has been discussed,Simultaneously a measure that should badopted to reduce the noise of high-pressure&great-flow axial flow ven tilators and a limited standard value for A-weighted Sound level have been also presented,This can not only keep the noise of ventilators up to A-weighted sound level.but also can decrcase the noise of ventilators properly. Purthermore this can make the noise standard for axlal flow ventilators be more scientific and more practica ble.