Abstract: Halliday's view on the Cardiff Grammar is one of the important concerns among scholars in Systemic Functional Linguistics. This paper systematically investigates Halliday's view on the Cardiff Grammar from the following aspects: linguistic stratification, the meta-function of language, functional syntax, natural language processing and cognitive research. The study shows that generally Halliday regards the Cardiff Grammar as a model within the same systemic-functional framework, which is complementary to the general theory. Specifically, for Halliday the stratificational and meta-functional differences maintained in the Cardiff Grammar have its own particular objectives to serve, the Cardiff Grammar has made great contributions to Systemic Functional Linguistics in functional syntax and natural language processing, and the Cardiff Grammar's cognitive model is closer to mainstream cognitive science.