The invention provides a cylindrical wrench for a transmission tower double-cap bolt. The wrench comprises a rapid self-tightening operation handle mechanism and an adjustable six-claw locking mechanism. The rapid self-tightening operation handle mechanism comprises an eccentric locking block, a handle and a moving head. The adjustable six-claw locking mechanism comprises a limiting ring, an adjusting sleeve, a sleeve tube body and moving clamping claws; six moving clamping claws are installed in a sliding groove of the sleeve tube body and are uniformly arranged with the spacing angle of 60 degrees; the adjusting sleeve sleeves the sleeve tube, the lower end face of the adjusting sleeve cooperates with the upper end faces of the moving clamping claws through vortex lines, the clamping claws can be driven to move radially by rotating the adjusting sleeve to change the clamping diameter, and therefore self locking can be achieved. The wrench has the advantages that the problems that theuniversality of a fixed bayonet wrench is poor, a moving wrench is not suitable for the operation in narrow space, the end face of a nut is easily damaged, and the double-nut construction with staggered angle fails to be achieved by the cylindrical wrench are solved.