This study investigates the acquisition of conventional metaphorical expressions by Chinese learners of English. A conventional metaphorical expression, following the definition of cognitive semantics, refers to the use of a conventionalised non-literal meaning of a lexical item in a multi-word phrase. For example, the word ‘attack’ in the phrase ‘attack one’s idea’, which should be interpreted as ‘to criticise somebody or something severely’, clearly departs from the literal meaning ‘to use violence to try to hurt or kill somebody’, and thus should be seen as a metaphorically used word. Consequently, the phrase ‘attack one’s idea’ is a conventional metaphorical expression. This study explores learners’ behaviour towards and acquisition of metaphorical expressions from two major perspectives: (1) possible cross-linguistic influence in the process of acquisition and factors that could affect cross-linguistic influence; and (2) the organisation of learners’ bilingual lexicon and the status of metaphorical expressions in a bilingual lexicon. These two perspectives are considered to be the main factors that can influence learners’ acquisition of metaphorical expressions: in order to acquire a metaphorical expression, learners should be able to integrate it into the bilingual lexicon, while the process of integration can be impacted by cross-linguistic influence. Previous research has mainly been conducted on the acquisition of certain figurative expressions in a second language, predominantly idioms; however, a combination of the two perspectives and a joint analysis on the acquisition of figurative language has yet to be accomplished. This study presents a first attempt of such analysis on the acquisition of a specific type of figurative language. The results of the experiments reported in this dissertation show that learners react differently to metaphorical expressions with different cross-linguistic availabilities (shared between Chinese and English or exclusively available in Chinese or English) but in general they encounter difficulty to achieve native-like performance when reading metaphorical expressions available in their second language. Persistent cross-linguistic influence is observed in two aspects, even among highly proficient learners: (1) learners encounter obstacles when acquiring the metaphorical expressions that are only available in their second language; and (2) learners seem to still activate the metaphorical meanings that are only available in their first language even when they read in their second language. These results altogether reflect that metaphorical expressions, regardless of cross-linguistic availability, are more difficult to acquire than literal expressions in a second language.