The invention discloses an automatic installation mechanism of a tool bit. The automatic installation mechanism mainly comprises a base and a carrier plate, wherein a carrier plate groove and a tool bit groove, which form a T-shaped groove structure in a horizontal and vertical manner, are arranged in the base; the carrier plate groove is horizontally extended, and is provided with two free ends and a first knife outlet which is communicated with the tool bit groove, and one free end of the carrier plate groove is opened to form a second knife outlet; a knife push part is arranged in the tool bit groove, and the knife push part is connected with a first drive unit capable of driving the knife push part to move in the tool bit groove back and forth; the carrier plate is movably embedded into the carrier plate groove, a stepped knife placing position is arranged on one end of the carrier plate, and the carrier plate is connected with a second drive unit capable of driving the knife placing position to slide inside and outside the carrier plate groove back and forth. According to the automatic installation mechanism of the tool bit, simple, quick, stable and reliable automatic installation is realized, the automatic installation mechanism has the advantages of simple structure, simplicity in operation, stable and reliable installation and the like. The tool bit groove is further improved, so that the whole installation process is full-automatic quick streamlined operation.