Reading comprehension ability, as a key skill that needs to be developed in English teaching, has attracted high attention from teachers and students in universities. This is not only due to its relatively large proportion in English exams, but also due to the entering of the information age, people need to obtain information from the text through extensive reading and gain a profound understanding of the content of the article. Therefore, in the process of guiding students to learn English knowledge, teachers must take cultivating students' reading comprehension ability as the central link of teaching activities. Through exploring and researching it in teaching, students can improve their reading comprehension level and enable them to have a deeper understanding of the profound connotations to be expressed in future English texts.

Extensive reading has enjoyed the increasing popularity from L2 educators as a potentially effective form of L2 reading instruction. However, many researchers tend to ignore the importance of selection of material. The paper is an attempt to explore the appropriate criteria of qualified graded readers, which can be helpful for English teachers and learners in ER program.