The invention provides a turning tool angle demonstration instrument. The turning tool angle demonstration instrument is composed of a cuboid component (1) used for representing a tool bar, a connecting rod (4) used for representing a main cutting edge, a front tool face plate (9) used for representing a front tool face and a main rear tool face plate (10) used for representing a main rear tool face. The changes of a cutting edge inclination, a front angle and a rear angle are achieved through the following structure and the connection relationship. According to the structure and the connection relationship, one end of the connecting rod is hinged to the cuboid component (1) in a swiveled mode, the other end of the connecting rod is connected with the front tool face plate and the main rear tool face plate, the upper surface and the lower surface of the front tool face plate and the upper surface and the lower surface of the main rear tool face plate are parallel to the axis of the connecting rod, the end, corresponding to the connecting rod, of the front tool face plate is connected with the connecting rod through a hinge (5), the other end of the front tool face plate can be inserted into one of multiple locating grooves (8), the locating grooves (8) are formed in a locating plate (7) fixed to the cuboid component, the main rear face plate is fixed to the connecting rod through a clamping sleeve (6), and the degree of the tightness of the clamping sleeve (6) is adjusted through a screw. According to the turning tool angle demonstration instrument, the front tool face and the rear tool face of a turning tool and three reference planes are represented by splice plates, and therefore the problem that the angle of the tool is not specific and is difficult to understand is solved; in addition, the turning tool angle demonstration instrument is easy to manufacture, convenient to use, and remarkable in effect.