In this study, it was investigated the features and types of external expression, the type of content and features shown in expressive writing written in the wrap-up stage in the elementary science classes. Students' perceptions of the expressive writing were also investigated. The subject of this study was 50 second grade students at a elementary school in Incheon. Four lessons of textbook-centered classes were proceeded, and the expressive writing activities were applied in wrap-up stage. Students’ expressive writing and their perceptions of the writing were analyzed. In results, essay, cartoons, and pictures types account for the largest proportion of the features and types of external expression shown in expressive writing. The content types of expressive writing were summary of the knowledge, things to learn, thoughts and feelings, questions and answers, experiments, and what they want to know and so on. Among those types, it is mainly used summary of the knowledge. In the result of the analysis about perceptions of the writing, it was found that students were aware of expressive writing positively. Students were interested in various ways of expression like essay, pictures, cartoons, tables, mind maps, and quizzes. They also thought that it helps their learning. But students have the burden with the thought that they should write with verbal form. Therefore, teachers need to encourage their students to use the various ways of expressing their ideas like writing thoughts and feelings, experiment, what they want to know rather than using summary of the knowledge and memorizing.