Abstract: Flow in porous media (or porous flow) is the manner in which fluids behave when flowing through a porous media. There are many types of porous media, such as rocks (including various types of minerals), soils, biological materials, and artificial porous media materials. The porous flow phenomena widely exist in the natural world, engineering materials and inside the body of plant and animals. The porous flow theory is fundamentally important in exploiting underground resources, such as underground water, geothermal resource, petroleum, natural gas and coal. This article explains the basic concepts, classifications, influencing factors and key characteristics associated with porous flow. The research significance of porous flow is also discussed.