Abstract: A new aerodynamic design system developed by authors for draft fan with enhanced efficiency,suppressed noise,enlarged flux and high load.The new design system features:A twist regulation for vortex control is employed in designing to lessen the secondary flow loss in the blade tip and hub;The feasibility and high efficiency of this procedure has been verified by the tests of the prototype fan;A new computer-aided 3D blading is used to optimize the blade;Numerical inverse checking is adopted to enhance accuracy in designing and cut down the period of the designing and production.This design system can make the optimized blade with 'forward inclination ', 'inclining sweep ','bending sweep ',to minimize the various secondary flow losses,to expand the steady working range of the fan,and to suppress the aerodynamic noise source.