The invention discloses a pipe reduction device for improving density of filled powder in getter mercury dispenser, comprising a feeding device and a clamping mechanism, wherein the feeding device causes a metal casing filled with powder to carry out axial movement, and the clamping mechanism applies radial force on the metal casing. The invention is characterized in that the clamping mechanism applies radial pressure on the metal casing to reduce the diameter of the metal casing so as to increase the density of the filled powder in the getter mercury dispenser. The invention increases the filled powder density by about 30%; and because the filled powder density is improved, mutual adhesive force is improved, the picking phenomenon has small possibility of occurring, the quality of the getter mercury dispenser is improved, and the application range thereof is expanded.