Liquid emulsion membranes were applied to the separation of penicillin G, and a model was proposed to describe the transport of penicillin G facilitated by two carriers. A polyamine-type surfactant such as ECA 4360J acts not only as carrier but also as surface-stabilizing agent, thus the influence of surfactant on the transport rate should be considered in mathematical modeling when its effect is significant. The proposed model is based on the shrinking core approach (advancing reaction front model) and takes into account the resistances of mass transfer in the water boundary layer, the thin oil film, and the emulsion. An equation expressing the overall mass transfer coefficient is given so as to simplify the model equations. The model shows good agreements with the experimental data. However, the calculated results underestimated the experimental data when the effect of the surfactant on transport rate is ignored. This indicates that the surfactant plays an important role in penicillin G transport. The model considering the contribution of surfactant is able to account for the increase in transport rate with surfactant concentration.