Abstract: In this paper，a damping vibration device for measuring the viscosity coefficient of liquid is designed.A spring vibrator is taken as the core，and a photoelectric proximity switch is used to collect data.A digital oscilloscope is employed to display the image and transmit the image data to computer for analysis.This method has a wide range of application，is convenient for collecting and analyzing experimental data.It also avoids various interference factors in the experiment and eliminated the disadvantages of traditional fallingsphere method.It also improves the accuracy of experimental measurement.

Key words: under-damping vibration, liquid viscosity coefficient, photoelectric proximity switch, digital oscilloscope