Abstract: Bernstein's code theory hypothesis: Students from a working-class background are disadvantaged in the school due to the gap between the limited coding they have acquired and the exquisite coding of the school. This assumption ignores the differences in the teaching process between schools. In the textual analysis of the classroom records of two different types of schools, It was found that there was different limitations and ambiguities in the logic of problem expression in the teaching process, the difference of analysis and description in the organizational structure of knowledge, and the discrepancy of focus and looseness in the rules of the teaching process resulting in two very different ways of teaching transmission: vertical transmission and horizontal transmission. The teaching rhythm of the vertical transmission type is coherent, clear, and progressive while the teaching rhythm of the horizontal transmission type is loose, ambiguous and enumerated. When the students whose codes are restricted by the authorities encounter the teaching of horizontal transmission, the situation they form is more worthy of attention.