Universal Grammar, represented by Chomsky, believes that the human brain is born with a Language Acquisition Device. Under the stimulation of the language environment, the language function of the human brain dedicated to language learning will be activated and begin to acquire a language. Universal grammar is the core idea of Chomsky's generative linguistics theory, which is composed of a limited number of syntactic principles representing the common features of human language. It is precisely because the human brain naturally generates this universal grammar that human beings can acquire their own mother tongue when language input is poor or even lacks "negative corpus" (that is, the indication of language errors or faults). Chomsky once proposed a simple language acquisition model, namely "language input —Language Acquisition Device —language acquisition", which means that language input generates grammar through Language Acquisition Device, thus acquiring language. It is worth noting that Chomsky's theory is not specifically designed for the study of Second Language Acquisition, and he himself has not given any guidance in this field, but it provides theoretical support for the theory of Second Language Acquisition (Yang Chunyuan, 2020). Hence, learning the whole semester’s course of Second Language Acquisition, having seen universal grammar as a important content in my textbook, this paper tries to integrate these related theories and make a conclusion and comment or paraphrasing(not all the bibliographies are quoted directly in this paper, paraphrased or arranged instead)based on various bibliographies.