Through the DSC,XRD,SEM and other experimental methods,the microstructure characteristics of reactive powder concrete(RPC) are discussed.The results show that RPC has a super high performance because of its lower ratio of water-binder,high pack density,optimum hydration products mixture and being strengthened by steel fiber.The high performance results from the special hydration microstructure of RPC,and its super performance can be well explained by the centrum particle hypothesis.