Abstract: Studies on lexical ambiguity set to investigate the interactive and developmental nature of the bilingual mental lexicon remain underrepresented in the literature. On the basis of distinguishing different types of lexical ambiguity (homonymy, metaphorical polysemy and metonymic polysemy), this study employed a translation recognition task presented by E-Prime software to investigate the mental representation of ambiguous words in Chinese EFL learners. The results indicated significant difference for different types of ambiguous words and for subjects of different English proficiency levels, but not for the direction of translation. In light of the modified hierarchical model, the representational development of ambiguous words, the activation and inhibition of semantic representations and their implications for the acquisition of ambiguous words are discussed.