Abstract: This paper discusses Martin's (1992) discourse semantics. The author begins with a briefing of Martin's education, the meaning of the term "discourse semantics"as used by Martin, and the reasons why he proposes this theory, i.e. the triple articulation of language. Then there are discussions on the similarities and differences between grammatical structures and discourse structures, and the four discourse systems of negotiation, identification, conjunction and ideation in detail in particular. Lastly, the author talks about the interplay between lexicogrammar and discourse semantics, and notions like context, genre and ideology.