The coefficient of liquid expansion is the ratio of the volume change to its volume at 0 ° C for every 1 degree Celsius change in temperature. In this paper, the experimental device for measuring the liquid expansion coefficient is assembled. The capillary and the temperature sensitive bubble are assembled into a container for the temperature sensitive liquid for experiment. Then, the constant temperature water bath is used as the device for changing the temperature of the liquid, the experimental data is recorded, the data is processed, and the water is obtained. And the coefficient of expansion of ethanol. The experimental conclusion has an important reference for the design and calibration of the thermometer. The error between the experimental results and the standard values is 2.9% and 3.0%, respectively, and the relative error is small, indicating that the experimental scheme is feasible.