CO 2 Injection gas into the oil reservoirs is one of the important methods for the enhancement of oil recovery. Although the good results have been obtained in the field scale projects of CO 2 rather than other gases, there are some problems in this method that should be deal with. One of the most important problems is related to the undesired mobility of CO 2 due to the low density and viscosity of the injected gas. it leads to the gravity separation and the fingering phenomenon during gas injection. To reduce these undesirable effects, CO 2 injection is proposed to be modified and performed in the form of Co 2 foam. This Foam can be used to improve the efficiency of the gas injection process. The foam flooding method can improve the sweeping performance through increasing of the apparent viscosity of the injection fluid. So, the higher viscosity of the fluid leads to the reduction viscous fingering phenomena. In addition foam can increase the sweep efficiency in an inhomogeneous formation as a result of increasing of the injected fluid resistance against flowing in high permeable regions. In order to investigate the effect of foam injections in a visual fracture porous media, a Poly methyl methacrylate micro-model has been used. The presence of surfactants and nanoparticles is vital for the formation and stability of foam, respectively. In this study, at first the foamability and foam stability tests are performed to determine the optimum nanoparticle and surfactant concentrations which lead to the highest foam stability. Then, the oil recovery is obtained using the injection of foam into the micro-model at optimal concentrations of nanoparticles and surfactant. the sodium dodecyl sulfate surfactant and Silica (SiO 2 ) and Zinc oxide (ZnO) nanoparticles are used in the experiments. Moreover, the surface of SiO 2 nanoparticles is modified using the 3-aminopropyltriethoxysilane to improve the stability of CO 2 foam. The silica particles have hydrophilic tendency, So the surface modification of this nanoparticles can increase the hydrophobicity of silica, which in turn, it can increase the stability of foam. Foam half-life might be considered as an index for the foam stability. As the half-life increases, foam stability will also increase. performing the stability tests at 2360 ppm of surfactant and different concentrations of nanoparticles, it is determined that the half-life at optimum nanoparticle concentrations for the foam samples stabilized using the silica (0.06 %wt) and modified silica (0.05 %wt) are 120 and 140 minutes, respectively. in addition it is found that in the concentration of 4720 ppm of surfactant, the half-life are 150 and 270 minutes, respectively. Also, the results of foam flooding in the micromodel showes that, the amounts of recovered oil using the modified silica stabilized foam injection is greater than that of silica. It is speculated that the higher oil recovery using the surface modified silica is related to the higher tendency of the oil for entering into the foam lamella as a result of the adsorption of oil in the surface of modified silica particles. In this case, the oil will penetrate more quickly into the foam lamella and will increase the amount of recovery factor.