With the development of autonomous and intelligent attack technologies, the situation of cybersecurity is becoming increasingly severe, and the traditional defense system can no longer meet the current security requirements. To reverse the passive situation of the network defese, moving target defense(MTD) emerges as the time required, which increases the uncertainty, randomness, and diversity of network and system to resist the same type of attack, and greatly decreases the success rate of attack by effectively reducing its certainty, similarity, and static. At present, the vulnerability of MTD has not been systematically analyzed, and the specific application of MTD in new scenarios has not been summarized. Firstly, the background and basic theoretical knowledge of MTD are illustrated. Secondly, the research related to MTD is reviewed and the vulnerability is summarized. Then, we introduce how MTD can be applied to emerging fields such as cyber-physical systems, cloud environments, smart grids, and the defense of adversarial examples. Finally, the research prospects of MTD are analyzed.