Translation is a kind of thinking activity which conveys the thinking content expressed by one language through another language integrally and accurately. The major task of a translator is to turn the cultural content in one language into another, so whether it is faithful or not largely depends on the degrees of the translator’s grasp of the two languages and the subtle difference of the cultural content expressed in the languages. If the translator does not know about the background information, his understanding of the source text will be out of the question, not to mention idiom translation. In doing idiom translation one should understand large quantities of eastern and western cultures behind languages, especially the differences between them. Therefore, translators should not only be familiar with the source text and the target text but also be proficient in the cultures behind languages.
By comparative study, this paper redefines the creatures of idiom translation after the “culture turn”. It has different connotations on different levels, that is to say, idiom translation is not a kind of literal translation but a sophisticated concept. Besides, this paper attempts to ravel out the complex relationship between culture and translation through values, social customs, geographical environments, history and religious belief. This paper also presents the factors that can weigh in on idiom translation and the methods for translators to translate reasonably as a cultural mediator.

II. Culture and Idiom 

2.1 Definition of Culture
Culture is an extensive concept. It is a difficult thing to define culture strictly and accurately. Many philosophers, sociologists, anthropologists, historians and linguisticians are trying to define it from the angle of their own subjects. However, there is no completely satisfactory definition of culture until now. According to some statistics, different types of definitions about culture are more than 200 kinds.
“Culture is the summation of human life which is the combination of several aspects and sections. Culture includes seven elements, namely, economy, politics, technology, religion, morality, culture and art” (247), a great Chinese culture master Qian Mu once pointed out. Besides, Spair defined culture like this: Culture is the common psychological order kept by people who live in the same environment (45). Therefore, culture is not an inpidual characteristic but a common psychological procedure produced by human beings who have the similar experience and accept the same education. If people from different groups and countries have different education, society and work, they will have different psychological procedure.
In general, the connotation and features of culture are formed in a certain historical condition and they are influenced by geographical environment and living habits. Therefore, culture always changes with the development of history. This is how culture difference formed. Therefore, we can define culture difference as the differences of languages, knowledge, beliefs, views on life, values, modes of thinking, moralities and customs developed by human beings from different life styles and natural environments. Different nations originate their own cultural systems in their own living environments. Meanwhile, they are moulded by their own culture. The otherness of nature is caused by the differences of people’s material lives and the varieties of social organizations. That is to say, it is the differences of geographical environments and culture origins that cause the differences of culture modes and characteristics, especially the differences of values, thinking modes, aesthetic tastes etc. 英汉文化差异在习语翻译中的体现研究(2):http://www.751com.cn/yingyu/lunwen_11696.html