Text adaptation is a common approach to developing language textbooks,a necessary process in language teaching,and a basic ability of language teachers.Based on the investigation of the adaptation 120 pieces of texts from the authentic texts,this paper puts forward four basic principles:comprehensibility,normativity,teachability,and moderateness,and forms nine main paths related to the principles closely,which is to reduce language difficulty,increase redundant information,enhance discourse cohesion,standardize the expression of vocabulary and grammar,meet the pedagogical needs of vocabulary and grammar,as well as measure the extent and evaluate the validity of adaptation.