The wave vector and amplitude of capillary wave reflect the surface tension and viscosity characteristics of liquid.The surface wave is equivalent to a reflective grating,its wave vector and amplitude can be measured by the diffraction signal of a laser beam,so as to obtain the surface tension coefficient and viscosity coefficient of liquid.Based on this principle,a set of experimental teaching device for optical measurement of liquid surface tension coefficient and viscosity coefficient is developed.The device realizes variable parameter measurement by introducing mechanical vibrator with adjustable frequency and proportion integral differential (PID) temperature control module.The edge detection and “centroid” like algorithm are used to determine the center position and intensity of the diffraction spot signal.The surface tension coefficient and viscosity coefficient of water at different temperatures and of alcohol at different concentrations are measured.The accuracy of the experimental device is verified,and it is suitable for promotion in experimental teaching.