A device for measuring the thermal expansion coefficient of solid by means of lever amplification is designed.The metal rod is heated to push the lever,and the ultrasonic displacement sensor is fixed at the other end of the lever.Based on the principle that the lever can significantly amplify the small elongation of the metal rod ,the small elongation of the metal rod is amplified to measure the small elongation of the metal rod.The data collection is programmed by Arduino to display the temperature and the amplified displacement in real time. Based on this instrument,the thermal expansion properties of solids can be studied and the thermal expansion coefficient of solids can be measured.The results show that the experimental phenomenon is obvious and the measurement results are accurate.The application of the instrument in physics experiment teaching can deepen students’understanding of the properties of solid thermal expansion and cultivate students ’ ability of innovative practice research.