Abstract: The sound velocity of materials is related to its Young's modulus and density, and the properties of materials can be evaluated by measuring the sound velocity of materials. Relevant researches show that the sound velocity of ultra-low expansion glass is the key parameter to evaluate its thermal expansion coefficient, and therefore the indirect nondestructive measurement of thermal expansion coefficient of ultra-low expansion glass can be realized by measuring its sound velocity. Considering that the ultrasonic velocity measuring instruments on the market are complex and difficult to integrate, an ultrasonic signal acquisition and display software is designed by combining high-precision data acquisition card, then a high-precision sound velocity measurement system with simple structure, convenient operation and easy integration is built based on the ultrasonic water immersion pulse reflection method. Finally, the sound velocity of the prepared ultra-low expansion glass samples are measured, and the result shows that the measurement system has high sound velocity resolution of 0.2 m.s^-1, which lays a research foundation for measuring the thermal expansion coefficient of ultra-low expansion glass via the high precision measurement of its ultrasonic velocity