The exploration and development of low grade oil and gas resources which have become important alternative resources in China have made great breakthrough. Research on numerical simulation of shale gas is helpful to realizing the dynamic process of shale gas development, laying a technical foundation for understanding seepage law of shale gas, optimizing mathematical model and evaluating as well as predicting productivity. Based on intensive investigation of literature from China and abroad, this paper systematically expounds the research progress of numerical simulation methods of shale gas and summarizes advantages and disadvantages of these methods. Shale gas numerical simulation models can be divided into equivalent continuous medium model, discrete fracture network model and mixed simulation model. The equivalent continuum model is simple in principle, pursues the macroscopic equivalent, neglects the true flow mechanism inside the reservoir, and is hence suitable for homogeneous shale gas reservoirs with low development of fractures. The discrete fracture network model accurately can reflect the porous flow characteristics of complex fracture networks and describe the objective regularity of highly discrete fractures and is hence suitable for shale gas reservoirs with completed exploration and high fracture development. The mixed simulation model combines the advantages of these two models to accurately reflect the complex fracture network and fluid migration law, meet the calculation accuracy, and save a lot of computing resources. With the improvement of computing and processing capabilities, the mixed simulation model is the future development trend. Finally, various problems in the numerical simulation model of shale gas reservoir are analyzed, and the development trends of shale gas numerical simulation are pointed out.