This paper presents a survey on the field of Augmented reality(AR)

which combines virtual computer generated material with the surrounding physical world

registers real and virtual object with each other and runs interactively at real time. Now it has become an important research field in VR and next generation of human computer interface. This paper introduces the primary content and state of art in this field. The key technologies

including basic tracking methods

display devices and registration processes

are discussed. Many typical AR applications and developing tools are listed. It describes the characteristic of AR system

with a detail analyzing of some technology difficult problems in AR system. The corresponding solutions are also mentioned. Currently research in AR field is largely focus on the AR system frameworks. Which usually gives a unified interface that supporting heterogeneous AR display devices in different AR applications. The AR frameworks also make the design of AR applications become more convenient. Two most influential AR frameworks

Studierstube and DWARF

are introduced. This survey provides a start point for anyone interested in AR research.