Relevance theory (Dan Sperber &; Deirdre Wilson 1995) originated from cognitive science. Its original purpose is not to study translation, but it has a strong explanatory power to "the most complicated phenomenon in the evolution history of the universe" (Richards 1953). Ernst-August Gutt studied translation according to this theory, and published his doctoral thesis Translation and Relevance: Cognition and Context in 199 1. In his book, Gert puts forward a refreshing relevance translation theory, which provides an organic and coherent theoretical framework for the study of translation ontology and methodology and has a certain influence in the translation field. Gert published the book again in 2000, and further elaborated some problems. Regrettably, the translation study of Relevance Theory has been neglected in China. This paper studies the flexible transplantation of cultural images in the translation of trademark words, aiming at proving the explanatory power of relevance theory to translation theory and practice and providing a new perspective for the translation of trademark words. Due to the multiplicity of meanings, the particularity of functions and the dependence on culture, the translation of trademark words is a complex problem, which is difficult to be explained by traditional translation theories. Therefore, choosing this highly explanatory relevance theory to explain and guide them can not only deepen the theoretical understanding of relevance translation theory, but also provide a new method for trademark translation practice. This paper is divided into six chapters. The first chapter is the introduction. This chapter first reviews the current situation of trademark translation theory, analyzes the shortcomings of Yan Fu's criteria of "faithfulness", "expressiveness" and "elegance" and Nida's equivalence theory in explaining and guiding trademark translation, and puts forward the writing purpose of applying relevance theory to explain and guide the flexible transplantation of cultural images in trademark translation. The second chapter is the theoretical basis of this paper, namely the ontological exploration of translation. In the first part, the author discusses the historical evolution of relevance concept. The second part tells the basic idea of relevance theory. The third part discusses the relationship between relevance theory and translation. In this part, based on Gert's translation theory, the author affirms the inferential nature of translation communication, and points out that the translation process is a cross-language and cross-cultural semantic interpretation process, seeking the best connection with the cultural context of the source language and the target language. The third chapter starts with the concepts and essence of trademark words and cultural images, points out that cultural images are an important part of the meaning of trademark words and play a key role in realizing the functions of trademark words, and then draws the view that trademark translation must attach importance to the transplantation of cultural images of trademark words. Chapter four, based on relevance translation theory, discusses the portability and flexibility of cultural images of trademark words. In the first section, the author discusses the translatability of trademark words and the transplantability of cultural images from the perspective of relevance theory, and points out that according to Cartford's translatability theory, the translatability of trademark words is relative, so the transplantation of cultural images must also be flexible. The second section points out that the harmony and conflict between different cultures require the flexible transplantation of cultural images in the translation of trademark words in order to obtain the best correlation between the translation and the target culture and realize the communicative effect of trademark translation. At the same time, this section also discusses the dialectical relationship between semantic relevance and functional relevance, and puts forward the view that semantics must give way to function in cultural image transplantation. Under the guidance of Relevance Theory, the third part discusses the necessity and feasibility of flexible transplantation of cultural images in transliteration and free translation, two commonly used methods in trademark translation. The fifth chapter studies the methodology of flexible transplantation of cultural images in trademark translation on the basis of relevance translation ontology, and puts forward specific methods of flexible transplantation of cultural images: image copying, image compensation, image deletion, image reconstruction and image addition. The sixth chapter summarizes the full text. Of course, as a new translation theory, the translation study of Relevance Theory is not ideal at present. Relevance theory may not cover all translation phenomena and solve all translation problems, but it has not yet found a more explanatory theory, which can be seen from the case exploration of flexible transplantation of cultural images of trademark words in trademark translation. The author hopes that academic colleagues and predecessors can further fully demonstrate and criticize it, even abandon it, or develop and improve it.