The term 'authenticity' has sparked off a lot of discussion in the fields of linguistics, material design, and language teaching. However, it seems that a consensus has not yet been reached on a precise definition. In this article, different definitions of authentic materials are discussed and it is believed that authentic materials used in ESP should not only be text- authentic, but also learner-authentic. A practice based on the principle is presented in this article and it is proposed that to supplement the weaknesses of the standard textbook, ensuring the learner-authenticity of ESP materials. So students' should be involved in preparing ESP authentic materials.
