Highly efficient photoluminescence (PL) in the visible light range has been found in porous silicon (PS). Several models have been proposed to explain the experiment results. The experimental results and the analysis based on a simple tunneling model by Vial et al are instructive for testing the rationality of these models, however the important effect of interaction between electron and hole, i.e., the exciton effect, is totally neglected in their work. In this paper, based on a double quantum well (DQW) model, the electron transmission coefficient of tunneling through the SiO 2 barrier is calculated taking account of the interaction between electron and hole. Then, the possible position of the luminescence center in the SiO 2 barrier layer is estimated in terms of the value of β parameter obtained by Vial et al from their experimental results. All these calculations are fundamental for further calculation of the quantum efficiency of PL in PS.