The angle demonstration model is a teaching tool that visually displays the concept and measurement of angles. It consists of two rotatable rulers, which are connected by a pivot at the end and can be flexibly opened and closed to adjust the angle. In teaching, rotating a ruler can demonstrate different forms of angles such as acute, right, and obtuse angles. Compare the sizes of different angles and demonstrate the stacking and splitting of angles, such as two 45 ° angles pieced together to form a right angle. Suitable for cognitive teaching in the lower grades of primary school, it can concretize abstract concepts of angles, help students establish a sense of quantity in angles, cultivate observation and hands-on abilities.