Abstract: As a heterogenous material, fiber-reinforcedcomposites (FRC) have a　significant structural mechanism. The mechanical behaviour and failure　machanism of FRC depend significantly on its meso-structure and　the properties of each constituent. It is a new trend to study the　relationship between the macro-mechanical behaviour and the properties　of the constituents as well as the meso-structual parameters. In this　paper, some developments in the mechanism of strengthening and　toughening of FRC, mainly for fiber-reinforced concrete, are reviewed.In addition, the developing trends of this subject are discussed.