On the basis of the wide spectrum eddy contact concept and the isotropic turbulence theory, a multi-scale theoretical model for the prediction of liquid-side mass transfer coefficient in gas-liquid system was developed. The model was derived from an unsteady-state convection and diffusion equation and considered the contributions of eddies with different sizes to the overall mass transfer coefficient. The proper contact time distribution at the surface is need to be determined to obtain satisfactory results with this model. Moreover, a simplified model was also proposed based on the assumption of steady-state mass transfer mechanism for single eddy. The results predicted by this model showed a very good agreement with the available experimental data in a comparatively wide range of turbulence intensities. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 886-896, 2011