Concepts and their relations are basic contents expressed in a text, structures of which are decided by concept contents and categories. Based on concept words, relations among words whether they are grouped in syntagmatic or paradigmatic relations, are upper words and lower words in a pragmatic sense, and category concepts and subcategory concepts in a logic sense. So text concepts bear functions of organizing text structures. Research into a text is, in a sense, the study of concepts, concept categories and laws, which helps broaden the scope of study of text construction and form practical strategy for translation.