The invention relates to a numerical control machining center tool changing and machining process demonstration teaching aid for relevant professional teaching of mechanical engineering of engineering colleges, and solves the problem that traditional classroom teaching is not visual and vivid enough and is difficultly understood by students. The technical scheme includes that in a tool magazine portion, a tool apron is lapped below a disc-shaped gear, the left side of the gear is engaged with a worm A, the worm A is connected with a motor E, a switch F is mounted below the motor E integrally mounted on a hollow square sleeve, the sleeve sleeves a guide rail, the left side of the sleeve is connected with a cylinder, the cylinder is mounted on the guide rail and connected with an air pump, in a spindle portion, a worm B is connected with a motor A, a worm slider is mounted on two supporting rods, a worktable is mounted on a worm slider mechanism, a chuck, a motor B and a vise are mounted on the worktable, and a support column, a switch, a worm E, a console and a worm C are lapped on a bottom plate. The demonstration teaching aid demonstrates all working processes of machining centers, and helps the students to understand tool changing, tool setting and tool tracks.