For giving a reasonable design method of electro-chemistry reactor, based on law of conservation of energy and law of conservation of charge, using a series of assumption, theoretical energy model was proposed in this study. By proper mathematics simplification method for the new model which demonstrats the relation between energy demanding and providing of the three-dimension electrode (TDE) reactor, the most important characteristic parameters (K-1, K-2) which are constant for a certain matter during electro-oxidation process were obtained. Experiments about phenol degradation using TDE reactor filling with granular activated carbon (GAC) were conducted to examine the fitness of new energy equation and experimental data. Results from experiments revealed that the oxidation behavior could be reasonably described using new model and the energy providing can be calculated by following equation: W = 1.56 x 10(14) eta(d(2) / V)C(0)EQ(2)(1 + root 1 + (V In K)/(3.63 x 10(13) eta(2)d(2)Q(2)C(0)E)). The calculated results obtained from above equation were in good agreement with experimental data especially at higher phenol removal efficiency. The new energy equation illustrates energy could be easily obtained through the solution of the value of characteristic parameters by simple lab-scale experiments. (c) 2006 Elsevier B. V. All rights reserved.