The invention discloses a multifunctional teaching aid. The multifunctional teaching aid comprises a sucker, wherein a circular truncated cone II is fixedly connected to the sucker; a rotary circular truncated cone I is mounted on the circular truncated cone II; a telescopic scale I and angle measurement marks are arranged on the circular truncated cone I; length scale marks I and angle measurement marks I are arranged on the scale I; a chalk holder is arranged at one end of the scale I; a telescopic scale II is arranged on the circular truncated cone II; and length scale marks and angle measurement marks II are arranged on the scale II. The multifunctional teaching aid has various functions of a compass, a ruler, a goniometer and the like; through the special design, the lengths of the scales can be adjusted, and the scales can be controlled to be separated from or completely retract into the circular truncated cones, so that much convenience and high reliability are achieved; owing to the combined detachable design, the multifunctional teaching aid is not only easy to manufacture and process but also easy to use and maintain; the multifunctional teaching aid can be folded or retract when not in use so as to occupy a small space and facilitate carrying; and the multifunctional teaching air is smart in structure, simple to operate and easy to popularize.