The text that students have once read during their classes are often used in summative assessment of reading expository text. In this paper, I investigated factors of continuing the summative assessment by interview with junior high school teachers and considered the solution of the assessment issue in reading instruction of expository texts. As the result of this investigate, I found four main factors: (1) difficult of teacher’s immature view of reading ability and assessment, (2) belief that student and their parents don’t understand the new assessment, (3) dilemma that colleague maintain previous method, (4) difficult of absence of new method in assessing reading expository text. Above all, study of reading instruction of expository texts is needed to approach (4) difficult of absence of new method. Also, the approach is needed to focus on critical reading.