Cognitive linguistics is extremely useful for vocabulary memory, especially the category theory and metaphorical system. Category theory has been applied to the learning of English vocabulary, emphasizing that there are inevitable causal links and kinds of similarities between different words after human conscious induction, i.e., there are relationships between words and words, words and contexts, words and the general meaning of texts, and words and the intention of expressions. In addition, cognitive linguistics believes that metaphors exist in any language. If conceptual metaphors are used well, they could make great progression on English vocabulary learning and for long-lasting patterns of thinking.