The significance of subtitle translation studies lies in several aspects. In the first place, it may draw more scholars’ attention to the field of film subtitle translation. In the second place, it can provide some principles and strategies for the translators in  the process of translation practice, so as to improve the translation quality. Last but not least, the audience is the best beneficiary; the refined translated subtitles enable them to better understand not only the language but also the social culture in the film.  
    In addition, along with China's position on the international stage is getting  higher and higher, the comprehensive national strength of our nation includes not only  hard  power  but also soft power. Soft power includes culture, history, value system and so on, which is more influential than hard power. By showing the charm of our  culture, the soft power of China will affect all over the world. Once we change the  pattern from culture import country to culture export country, our nation will be a  truly strong power in the world. The export of audio-visual works is a main way of  culture exports for western countries to receive the charm of China. It is a very  important problem to discuss how to translate these works properly in order to have the acceptation from foreign audiences.
2. SKOPOS THEORY    
2.1 The definition of Skopos theory
Skopos means “aim” or “purpose” in Greek word. Skopos theory is the core of German functionalism. As an important theory, it was first proposed by Hans J. Vermeer in the 1970s. In Hans J. Vermeer’s Skopos and Commission in Translation Action Vermeer puts the skopos theory in this way “Any form of translation action, including therefore translation itself, may be conceived as an action, as the name implies. Any action has an aim, a purpose. The word skopos, then, is a technical term for the aim or purpose of a translation.”  
The following is taken from Routledge Encyclopedia of Translation Studies : “Skopos theory is an approach to translation which was developed in Germany in the late 1970s, and which reflects a general shift from predominantly linguistic and formal translation theories to a more functionally and socioculturally oriented concept of translation. Translation is viewed not as process of transcoding, but as a specific form of human action. Likely any other human action, translation has a purpose, and the word skopos, derived from Greek, is used as the technical term for the purpose of a translation.”
In Mark Shuttleworth and Moria Cowie’s Dictionary of Translation Studies(1997: 156), the skopos theory is defined in this way: “Skopos theory (German skopostheorie, from Greek skopos “purpose, goal”): An approach to translation proposed in the late 1970s and early 1980s by Reiss and Vermeer. Skopos stresses the internationalism, pragmatic aspects of translation, arguing that the shape of target text should above all be determined by the function or “skopos” that it is intended to fulfill in the target context. Reiss and Vermeer formulate this principle into two skopos rules: ‘an interaction is determined by (or is a function of ) its purpose’, and ‘the skopos can be said to vary with the recipient’.”
Christiane Nord (2001,18) defines the Skopos Theory in her Translating as a Purposeful Activity: Functional Approaches Explained Vermeer (1989,134) as the theory that applies the notion of skopos to translation. He believes that the prime principle determining any translation process is the purpose (skopos) of the overall translational action. 目的论视角下影视字幕翻译研究《唐顿庄园》汉译(3):http://www.youerw.com/yingyu/lunwen_19979.html