Abstract:One of the main reasons resulting in the huge disputes and errors in both understanding and application of Relevance Theory is that there exist big defaults in such four important definitions of the theory as those of relevance, the individual relevance, the principle of relevance, and ostension-inference. There exist such problems as being deviated, too general or self-contradictory in the explanations in the above four original definitions. Therefore, this paper has amended and improved those four definitions based on the previous critical analysis conducted against those defaults. The amendment study is a necessary measure for the improvement of Relevance Theory as well as the final target in the critical research of the theory.