Abstract: There are two categories in language expression:the category of literalness and that of non-literalness, with only the latter being examined in this paper.The non-literalness means that while the actual sentence idea intended by the speaker is implied by another sentence in which the concept/s is/are completely different, the things and events referred to by the previous sentence are faintly discernible in the non-literalness, with the two representing both concept and presentation and having a causal relationship.This is the causal implication demonstrated in the non-literalness.The theory of causal implication is the key point for solving the problem of non-literalness.