This paper’s research subject is the triadic dialogue interpreting which involves the interpreter to interpret ‘bidirectionally’ and aims at investigating how interpreters make sense of the communicated messages in the interpreting process. In contrast to conference interpreting, in which meaning is generally fixed monologically by the speaker and the establishment of ‘sense’ is largely left to the end user, i.e., the audience or recipients, meaning the dialogue interpreting is created by circumstances and varies by all the participants. Therefore, this paper aims at investigating the parameters in the interpreter’s sense making process and shows how these parameters interplay with each other to influence the interpreter’s coherence establishment. The dialogue interpreter in this case, being a third party in the triadic communication, assumes the co-responsibility for establishing coherence, and thus is involved in the whole process. An authentic bilingual legal proceeding from a Hong Kong courtroom is selected to show how to identify and analyse the coherence parameters in reality.