This paper is to find and to suggest alternative ways of description on function chapters in the middle school mathematics so that the descriptions be more closely related to daily life. The research has two phases: one for belief on the usefulness, the other for cognitive ability to solve the practical problems. Results are as following. 1. Most descriptions of corresponding chapters have emphases on the usefulness of functions so as to enhance beliefs on the use of functions. 2. Most practical functions contain expressions of large constant term and large coefficients in magnitude while those are not in the descriptions of tektbooks, especially in case of using ruled papers. 3. For quadratic functions, most students do not detect the degree of the function from the data presented by pairs of values of x and y. And those are not dealt with in most of textbooks, which are given in the MIC textbook.