The breakthrough operations for gold tetrachloride in hydrochloric acid solution on a fixed bed were carried out with different kinds of MET resins, different radii of particles, different linear flow velocities, and different media concentrations at temperature of 25 +/- 0.5 degrees C. The values of HETP were calculated from the experimental breakthrough curves. It was demonstrated that the rate of mass transfer was controlled by the liquid diffusion process. Two sets of thicknesses of the liquid film were calculated from the experimental HETP values and the conditional parameters, respectively. By comparing the two sets of liquid film thicknesses, we find that the adsorption double layer on the resin/solution interface plays an important role in the liquid mass transfer process.