Abstract: Translator is the mediator who bridges the source text and the translated text, and transmits the information of the source text to the target readers. Translator's choice and employment of translation strategies are of great importance to the quality of science and technology translation. Amplification is one of the frequently-used skills in sci-tech translation. Through the analysis of some examples of amplification in English-Chinese translation, the article discusses the types and effect of amplification, and emphasizes that translators should give full play of their central role in sci-tech translation, trying their best to use translation strategies and skills flexibly and properly to convey the information of the source texts in the best way.