We present a unique electrochemical method for monodisperse bubble generation on a microfluidic chip and demonstrate its application in determination of liquid surface tension.Efficient generation of dispersed hydrogen microbubbles was achieved using Pt electrode via electrolysis of water,which was immersed in poly(dimethylsiloxane)(PDMS)film of the microchip.The release frequency of the hydrogen microbubble is directly related to liquid surface tension,and thus allowing a direct determination of liquid surface tension in microfluidics.As demonstration,isopentanol solution was used as a model surfactant system.An electrochemical method combined with the microscope imaging technique was used for monitoring the process of monodispersed hydrogen bubble nucleation,growth,formation,and final release.The measured surface tension values are in good agreement with those measured by the conventional maximum bubble pressure method.The present proposed approach on chip provides a simple,fast and accurate method for surface tension measurement of small sample in real-time.The research result is also helpful to the study of mass transfer behavior in microfluidics.