Abstract: An improved decorative button of a pet collar, including a decorative cap, a resilient pad member and a decorative attaching paper. The decorative cap has a projecting rectangular rivet stem and a lower arch surface around the rivet stem corresponding to a curve of the pet collar. The resilient pad member is formed with a central rectangular hole corresponding to the rivet stem of the decorative cap. The rectangular hole of the resilient pad member has four slightly upward bent side edges. Each of four corners of the rectangular hole is formed with a linear fissure and a middle portion of each long side edge of the rectangular hole is also formed with a linear fissure, whereby the rivet stem is irreversibly fitted into the rectangular hole of the resilient pad member. The resilient pad member is resiliently deformed in accordance with the curve of the decorative cap and the pet collar so as to closely associate therewith without producing any clearance or unplane projecting portion.