Nominal clause is a clause with nominal feature and syntactic analysis is the study of laws of sentence constructions. And Chomsky’s Generative Grammar is a very useful method to analyse a sentence in an explanatory way. This paper aims to focus on how to understand a nominal clause under Generative Grammar (GG) for the explanatory adequacy. In doing so, it will give a brief explanation to the generative mechanisms of simple sentence under GG, then move on to the similar mechanisms of complex sentence, here, it will focus on nominal clauses. On the syntactic analysis of nominal clauses, there are two steps: first recognizing its position in the whole sentence, then picking a proper connective for the nominal clause. Notice this paper will analyse a complex noun sentence for two sentences, one is the whole sentence, and another is the small clause, namely, the nominal clause within the whole sentence. Thus, it can conclude a way to analyse nominal clauses syntactically, and understand their inner constructions. Furthermore, it can explain why a nominal clause form like this and have a better understanding of complex sentences. More importantly, such method can play its role in linguistics and foreign language teaching, which would help language teachers build up a better understanding of the nature of language and the process of language learning.