Having the performance of real-time, autonomous, robust and high capability, cyber-physical Systems (CPS) are a kind of intelligent complex systems which combined sense and control, computation and communication with physical object tightly in network environment. The notion, development and framework of CPS are presented, and the different between CPS and embedded system, WSN and IoT are discussed at first. Then, the application and research of CPS in the fields of electric power, traffic, medical and aeronautic & astronautic are summarized, and the outstanding challenges about CPS are pointed out. Finally, the future research and development directions of CPS are discussed.