Abstract: Catchword, a kind of speech orientation, is a representation of times, value and dynamics of communication in the discourse space, and a free and initiative speech form. The tension of catchword can highlight human beings' subjective sense of motivation, which is the speech requirement in the freedom of communication. The association theory of Marxism, which judges the speech attitudes, mindsets and ideological beliefs of the subjects based on their economic interest relationship, is a scientific method of treating catchwords. The demand for speech must be restricted by the demand of interest, and the ideological demand can always reflect the interest demand. For building our discourse system in the socialism with Chinese characteristics, we need to control the tension and limitations of catchwords to fully stimulate the vitality of speech in the new era.