The invention relates to an adjustable expanded slag bead chute, in particular to processing equipment for dry granulation of blast furnace slag. The invention aims to provide the adjustable expanded slag bead chute which has simple structure, is convenient to operate and can avoid slag wool and control the volume weight and grain size of the slag beads. The chute comprises an upper expansion chute and a lower expansion chute, wherein the upper expansion chute is fixedly installed below a blast furnace slag channel in a downward inclining manner; the width of the upper expansion chute is more than that of the blast furnace slag channel; the lower expansion chute is arranged below the outlet of the upper expansion chute in a downward inclining manner and is installed on a movable trolley by a tilt angle adjusting device; and expansion chute cooling systems are arranged in the bodies of the upper expansion chute and the lower expansion chute.