Abstract: Applied linguistics has become more and more important in language sciences since the middle of twentieth century. Its rapid development indicates that applied linguistics can be combined with transdisciplinary themes, such as psychology, sociology, cognitive linguistics and computational linguistics. Likewise, Complexity Theory/Dynamic Systems Theory is also the new transdisciplinary theme of applied linguistics, which not only helps us grasp applied linguistics from a dynamic view, but also helps us better understand the theory itself. Complexity Theory/Dynamic Systems Theory further helps understand the principles and content of applied linguistics. It is concluded that the theory offers a new pointcut to the research of applied linguistics and helps understand the discipline from a different point of view, producing positive influence towards language learning process.