Abstract: The macroscopic mechanical properties of reinforced concrete members are determined by the mechanical properties of steel rebar and concrete. In light of the mesoscopic heterogeneity, concrete is regarded as a triphase composite material consisting of aggregate, mortar matrix and the interfacial transition zone (ITZ) at meso-scale. It is assumed that the steel rebar and concrete are well bonded. A meso-scale numerical model of reinforced concrete columns subjected to eccentric compressive loading is established. Several uniaxial compressive tests of square and rectangular concrete specimens are conducted. The mechanical parameters of the ITZs are fixed by an inversion method. The macroscopic mechanical properties of reinforced concrete column subjected to eccentric compressive loading are simulated. The simulation results indicate that the material heterogeneities can be revealed sufficiently by the established meso-scale numerical model compared with those obtained from the macro-scale model, and the macroscopic mechanical properties of the test specimen can be well simulated. The failure process of the specimens can be described elaborately. Moreover, the simulation results are consistent with the experimental observations. The meso-scale simulation method established in this study provides a theoretical support to the investigation of the size effect of reinforced concrete members.