The invention discloses a demonstrating device for mathematics teaching and relates to the mathematics field, in particular to a device for mathematics teaching. The demonstrating device for mathematics teaching comprises a base framework; an upper border of the base framework is fixedly connected with a top beam, a left side beam and a right side beam to define a rectangular frame structure; a curved line steel strip is arranged in the rectangular frame structure; a vertically arranged inner side groove is formed in the inner side of the left side beam; the side end of a rolling wheel is connected with a curved line pulling and pushing rod; a left-right-through vertical direction through groove is formed in the right side beam, and a steel strip guiding frame is arranged in the through groove; an up-down-through sliding groove is formed in the upper border of the base framework; a plurality of vertically arranged curved line pulling and pushing rods are arranged in the sliding groove; the rear side of the upper end of each curved line pulling and pushing rod is hinged to a curved line pressing carrier roller through a shaft; a plurality of cylinders are vertically arranged in the base framework; the upper ends of piston rods of the cylinders are connected with the curved line pulling and pushing rods; and rubber pads are arranged on the inner surfaces of the lower portion of concave ways and the cylinders in the shapes of inverted T. The problems that in an existing mathematics curved line drawing method, a point drawing method is commonly adopted, or drawing is performed through a French curve, operation is tedious, and time is wasted are solved.