Metaphor processing in translation has drawn much research attention. However, little attention has been paid to the cognitive processing routes of culturespecific linguistic metaphors (CSMs) in simultaneous interpreting (SI). The present study compared professional interpreters’ strategies for interpreting CSMs and literal expressions in the context of simultaneous interpreting (SI) and on this basis attempted to infer their underlying cognitive processing routes in SI with the help of a self-supported bilingual parallel SI corpus. The results showed that (1) the vertical route dominated the interpreting of literal expressions and CSMs, (2) the interpreters relied more on the vertical route in the interpreting of CSMs than that of literal expressions and (3) the grammatical unit of the source items had little influence on the cognitive process of interpreting linguistic metaphors.