Abstract: Being a real-time and robust autonomous system with high performances, cyber-physical systems (CPS) are a kind of novel intelligent complex systems with different scales of computation and physical components tightly integrated and interacted under the future networks. The notion and the characteristics of CPS as well as the development of this technology are first presented. Then, the technology framework of CPS and its relationship with other related systems and technologies are discussed. Finally, challenges to be dealt with for CPS are pointed out, and the future research directions are discussed.