A surgical milling cutter, comprising a milling cutter bracket, a locking apparatus, a locking seat and a bottom main machine that are successively connected, wherein the milling cutter bracket comprises a retaining seat with a through hole, a finger guide with an L-shaped bracket on top thereof is disposed above the upper part of the retaining seat, a protrusion extends downwardly from the end of the short side of the L-shaped bracket, and the lowest point of the protrusion is lower than the lowest point of a cylindrical bit of the milling cutter during the normal operation of the milling cutter; a bolt with a center through hole is fixed in a cavity of the finger guide; a pressing plate is disposed at the upper part of the retaining seat, and a nut passes through the hole of the pressing plate to connect to the bolt; the locking apparatus comprises a flange with a through hole, a first bearing is disposed at the inner wall of a small cylinder above the flange, a locking sleeve sleeves the flange, a protrusion is disposed on the inner wall at the upper part of the locking sleeve, and a conical surface is formed at the inner wall at the lower part of the locking sleeve; a third spring is disposed between the bottom of the conical surface and the upper bottom of the flange, and a pressing plate is threadedly connected to the outer wall on the top of the small cylinder above the flange and presses the protrusion; a conical hole corresponding to the conical surface is made on the wall of the small cylinder above the flange, and a steel ball is disposed in the conical hole; the locking seat comprises a connecting shaft having an upper connecting bit and a lower connecting bit, a second bearing disposed at the inner wall of the bottom of the locking seat and connected to the connecting shaft in an interference fit mode, the lower part of the connecting shaft is provided with a long waist-shaped hole, a pin passes through the long waist-shaped hole to fix the lower connecting bit with the connecting shaft, and a fourth spring sleeves the connecting shaft between upper connecting bit and the lower connecting bit; a groove corresponding to the conical hole is formed on the transmission rod of the milling cutter, and the lower end of the transmission rod is snap-connected to the upper end of the connecting shaft; the main machine comprises a main machine housing and an electric motor, a first protruding cylinder with a through hole at its center is disposed at the upper part of the main machine housing, a first bolt connects a pressing plate and the main machine housing together, a snap-fit notch is provided in the inner wall of the first protruding cylinder, an end with a barb of a snap retainer is disposed in the snap-fit notch, and a second bolt provided with a second spring passes through the first protruding cylinder to connect to the other end of the snap retainer; a protrusion is disposed at the inner wall of the locking seat; two positioning devices are disposed at the main machine housing, the positioning device comprises a second protruding cylinder disposed in a through hole of the lower cylinder of the first protruding cylinder, a first spring is disposed between the first protruding cylinder and the main machine housing, and the upper part of the second protruding cylinder passes through the pressing plate; the bottom of the locking seat is provided with a groove corresponding to the second protruding cylinder.