The invention discloses a gear transmission teaching instrument, which comprises a box body, a gear shaft A, a gear shaft B, a gear shaft C, a speed sensor A, a servo motor, a control display device, a speed sensor B, a worm shaft, a transmission gear, a large gear, a worm, a worm gear, a small bevel gear and a large bevel gear. The gear transmission teaching instrument has the advantages of simple structure, convenient use and the like. By means of the gear transmission teaching instrument, the transmission of bevel gears, the transmission of cylindrical spur gears and the transmission of worm gears can be vividly and visually displayed. The transmission of bevel gears, the transmission of cylindrical spur gears and the transmission of worm gears can be simultaneously displayed based on the reasonable design of transmission shafts and the reasonable installation of gears. Meanwhile, based on the reasonable design of speed sensors, the obtained speed is displayed by the control display device. Therefore, learners can better understand the knowledge more easily, and whether data calculated by the learners are correct or not can be checked.