Equivalence is a central concept in translation theory,but it is also a controversial one.Influ- enced by many different factors,equivalence in translation is actually a variant characteristic of relativi- ty and stratification.Traditional prescriptive translation theories always focus on the source language (SL),define the conditions of equivalence before translation to direct translators' practice and evaluate different translated texts after translation.However,translation is constrained,to a large extent,by lin- guiatic and cultural norms in the target language (TL),thus absolute equivalence can sometimes not be achieved.Therefore,we should change our perspectives in translation studies,divert our attention to the TL,observe and describe the actual correspondence between SL and TL texts,including cases of both equivalence and non-equivalence,then try to explain the constraints and explore the universal laws of equivalence which will then be tested in the translation practice.