The microstructure of reservoir rocks plays an important role in oil and gas accumulation and production. We examine a universal method to evaluate these properties of rocks, such as pore tortuosity, matrix porosity, and connectivity, and we respectively construct a 2D numerical reconstruction rock model with different microstructure parameters by the Monte Carlo method and the quartet structure generation set method. We further study the heterogeneity (characterized by fractal dimension and tortuosity) of the constructed image for reservoir rocks by the numerical and theoretical analysis and obtain the formulas for fractal dimension and tortuosity versus porosity. The simulation results show that the logarithmic relation is between the pore fractal dimension and porosity, and the relationship between tortuosity and porosity has the form of power. This process provided an important method to advance 2D reconstruction technology of reservoir rocks and effectively determine the relationship between microstructure and porosity.