In this work, the heat-transfer performance of liquid-liquid microdispersed systems was tested for the first time with a microdispersion contactor named a membrane dispersion minicontactor and octane/water as the working system. The volumetric heat-transfer coefficients ranging from 5 to 25 MW/(m3.degrees C) were obtained, which were 15-20 times higher than that of the conventional dispersion heat-transfer methods. The heat-transfer Murphree efficiencies, defined to evaluate the heat-transfer performance, reached 85-99% for the microdispersed system with residence times less than 0.1 s. By introducing the two parameters of Ca number and oil volumetric fraction, a semiempirical model for predicting the volumetric heat-transfer coefficient has been developed, which fits the experimental results very well. Furthermore, the similarity between the heat and mass transfer in the microdispersed system was demonstrated.