The invention relates to a changed position fixing device of a catwalk of a suspension bridge and a method thereof; one cross beam is respectively arranged at the side span of a bridge closing to a main tower and on a catwalk beneath a cable clip of a splay saddle; the bearing rope is fixed with the cross beam by a U-shaped bolt from lower direction of the catwalk bearing rope; lower ends of two pull rods are respectively connected with two ends of the cross beam through a bolt, the upper ends of two pull rods are respectively connected to both sides of the cable clip at the upper part through the bolt; then catwalk mesh layers on three bearing ropes at inside of the catwalk to be changed and removed are dismounted; and then three bearing ropes at inside are gradually loosened; at last, the three bearing ropes at inside of the catwalk are respectively connected with three bearing ropes at outside firmly, thus the change position is completed.