Order to study the effect mechanism of three-dimensional electrochemical reactor is better than that of two- dimensional electrochemical one in contaminant treatment,the paper quentitatively studied the transfer ability of three-dimensional electrochemical reactor and two-dimensional electrochemical one by taking mass-transfer coefficient as index.It also investigated the main influential factors that affect mass-transfer coefficient by orthogonal experiment and single factor experiment,and analyzed the electrochemical model by use of dimensional analysis. The results show that mass-transfer coefficient of three-dimensional electrode reactor filled with foamy copper and activated carbon is always higher than that of two-dimensional electrode reactor in the same condition. Temperature is the main influencial factor to mass-transfer coefficient, dimension is the next and then is flow. Higher temperature.The higher the temperature,the more the flow rate and mass-transfer coefficient,and the strong the mass-transfer ability of the system. The error between the experimental value of Sherwood and that of theory is 0~14.65%,which achieves good agreement.