The invention discloses a mathematics probability teaching demonstration device, comprising a bottom plate; support legs are integratedly formed on the lower end of the bottom plate; the lower end of the bottom plate is provided with an iron plate through adhesion; the lower end of the iron plate is provided with a magnet; the upper end of the bottom plate is provided with a connection handle through welding; the connection handle is provided with a positioning plate through a bearing; the outer rim of the positioning plate is provided with positioning holes; the connection handle is provided with a positioning bolt matching with the positioning holes; and a main shaft is integratedly formed on the upper end of the positioning plate. The mathematics probability teaching demonstration device realizes the direct demonstration function during the probability teaching through designing a random rotation plate of an inner-outer plate. Besides, the mathematics probability teaching demonstration device also has the function of regulating the inclination angle of the plate, and regulates the inclination angle of the demonstration plate in real time according to the requirement. The invention is simple in structure, gives a strong visual impression, and maximally satisfies various demonstration requirements on the class.