reducing the wind resistance and guaranteeing the full load operation of the fan according to the size and the weight of the fan a middle sized fan can utilize a plurality of electric motors to control the angle of the blades 2 and the output shaft of each electric motor is respectively connected and matched with the first lead screw 33 and transfers the power the present embodiment enumerates another mode of execution of the blade adjusting mechanism and as shown in fig1 14 the lead screw nut assembly includes a second lead screw 52 and a second nut 55 the slide device includes second slide rod bearings 56 and slide discs 57 the substrate assembly includes a second drive motor fixing disc 60 a front bearing seat 54 a rear bearing seat 51 a supporting disc 64 and supporting rods 65 the transmission assembly is a connecting rod type transmission assembly and includes connecting rods 58 connecting rod connecting pins 59 rotating arm connecting pins 60 rotating arms 61 coupling shafts 62 coupling bearing seats 71 second bearings 70 and blade shaft sleeves 69 and the adjusting mechanism is coated with a shell and the shell includes a front end cover 68 a second cabin.