The device can realize automatic quantification, weighing and packaging, The material is put into weighing box of machine from inlet, when the weight reaches preset amount, the inlet is closed. After the control system receives the signal that bag is prepared, the material is discharged from outlet into the bag. When all the material enters the bag,the control system opens pneumatic valve, transports the bag by the conveyor and brings it to the sewing machine for sewing, This machine can pack 450-500 bags of materials per hour, and it reduce the labor cost effectively and packing accuracy control.