Semantics,the study of meaning,is closely connected with translation,the practice of transferring meaning.The paper uses a lot of examples based on real translation practice to prove that semantics plays a very important role in translation practice.Understanding and making good use of semantic relations,including synonymy,polysemy,homonymy and antonymy,are quite important for a translator to deal with some complicated semantic problems in translation practice.The paper also discusses the concept of denotative and connotative meanings,two basic types of meaning in Semantics.Denotation means the literal meaning of a word which is given in dictionaries;and connotation,the associative and suggestive meanings of a word in its context.Be cause of cultural difference,words with the same denotations may have totally different connotations,which is why the concept of denotation and connotation plays a very important role in English/Chinese translation.In order to translate a text into another language correctly,translator must totally understand the meaning of the original word,both denotative and connotative mean ing,and be aware of the potential connotations of the word in the target language.