Naturally fractured reservoirs exist throughout the world and represent significant amount of oil and gas reserves, water and other natural resources of world. In the past half century, the study of fluid flow and transport processes in fractured porous media has received great attention and has been one of the most active areas in investigating multiphase flow in reservoirs. This is because of its importance to underground natural-resource recovery, waste storage and disposal, environmental remediation, CO2 geosequestration, and many other subsurface applications. There has been an increasing interest in fracture flow in recent years, because of the needs to characterize flow through hydraulic fractured reservoirs with low-permeability or unconventionals in the petroleum industry. Since the 1960s, significant progress has been made towards understanding and modeling of flow and transport processes in fractured rock (Barenblatt et al. 1960; Warren and Root, 1963; Kazemi, 1969; Pruess, 1985; Narasimhan and Pruess, 1988; Kazemi et al. 1992). Despite these advances, modelling the coupled processes of multiphase fluid flow, heat transfer, and chemical migration in a fractured porous medium remains a conceptual and mathematical challenge. The challenge arises primarily from (1) the inherent heterogeneity and uncertainties associated with the characterization of a fracture-matrix system for any field-scale problem; (2) the difficulties in conceptualizing, understanding, and describing flow and transport processes in such a complicated formation system; and (3) the limitations from measurements of field fracture properties to computational intensity for incorporation of realistic 3-D field fractures in mathematical models. This talk will discuss (1) some history, (2) commonly used conceptual models; and (3) a unified modelling approach for fractured reservoir simulation.