The use of flow-through porous electrodes is identified as a promising approach to enhance the performance of microfluidic fuel cell (MFC). In this study, a dimensionless computational model is developed to analyze the distribution characteristics of the electrochemical reactions in flow-through porous electrodes of MFC. One important finding is that the electrochemical reactions mainly occur in the vicinity of the anode and cathode outlets. Based on this observation, the new design of partial modification at reactive sites is proposed to reduce the MFC cost. It is found that MFC with partial modification can achieve comparable performance with that of conventional full electrode modification, demonstrating the feasibility of partial modification method. The partial modification also offers a promising alternative to avoid unwanted secondary reaction, such as hydrogen evolution. (C) 2015 Published by Elsevier Ltd.