Micropore dispersion reactors have been considered as one of the most promising micro-structured devices. For reliable design of this kind of microreactors, the micromixing performance in those microreactors with different detailed geometric structures have been investigated in this work. The pore size, pore shape, pore number and pore distance were varied and the micromixing performance was characterized by the Villermaux/Dushman parallel competing reaction. The results showed that the mixing performance was greatly influenced by the geometric structures. The segregation indexes, X-S, were found in the range of 10(-2) to 10(-3). indicating that the micropore dispersion reactors have high micromixing efficiency. To deeply understand the micromixing process. CFD simulation was carried out to describe the flow fields in the reactors. Based on the simulation results a mathematical model was developed and a new area parameter,S, was defined by considering both mixing region surface and mass transfer distance. A linear relationship between S and Ig(X-S) was obtained at last, which is very helpful for optimizing the structure design of micropore dispersion reactors. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.