Equivalence translation is one of the topics disputed about the translation theories. This paper organizes the historical root and the main types of the concept of equivalence. The paper makes the epistemological foundations of the equivalence translation theories clearly, and points out the problems in them. The paper, based upon the Buddhist Epistemology, points out that there are two kinds of relations between SL and TL: the proceeded-relation from SL to TL and the invested-relation from TL to SL in the translation process, but the equivalence translation theories just have been concerned with the former up to now. The paper names the theory which shows the relations between SL and TL as Theory of Proceeded-invested-equivalence, and it proposes that the new equivalence translation theory is more proper and more reliable so that the old will be reconsidered.