本文基于十八届三中全会文件的双译本汉英平行语料库，从译语语言形式参数和翻译偏移入手来比较政治文献官方英译和海外译者英译的翻译风格，并探讨二者差异背后的原因。研究发现，海外译者Rogier Creemers在政治文献汉英翻译中相当保守，追求字面对应，因而译文句子较长，“中式英语”痕迹较重，可读性较差，而中国官方翻译团队则相对灵活，在忠实表达原文意思的前提下适当拆分长句，并频繁采用增补解释类偏移和删减简化类偏移，从而使译文更为明晰、简洁，可读性较强。相对而言，官方翻译更加贴近英语受众的思维习惯，也更有利于传递中国政府的积极形象。结合对官译团队专家和Rogier Creemers的采访，本文认为二者翻译风格迥异的主要原因在于翻译目的、翻译流程以及译者背景不同。

Based on a corpus of two translation versions of the three key documents released at the third plenary session of the 18th central committee of the CPC (the Communist Party of China), this article conducts a comparative study of the styles of the official translators and an independent overseas translator through the analysis of translation shifts as well as the linguistic features of the translated texts. It is found that the independent overseas translator is obsessed with formal correspondence, and his translation is characterized by long sentences, numerous Chinglish expressions and poor readability. By contrast, the official translators adopting a more flexible approach frequently opt for formal translation shifts (esp. addition and omission) so that their translation is more explicit and concise with fewer Chinglish expressions and better readability. Comparatively speaking, the official translation is more compatible with the linguistic habits of the target English readers and can more accurately convey the political and cultural messages in the Chinese political texts. Drawing on the interviews with an institutional insider of the official translation team and the independent overseas translator himself, we argue that these differences in translation styles can be attributed to their differences in translation skypos, translation procedure, and the linguistic background of the translator(s).