Reading summarization process involves complex cognitive activities. It is not only about understanding sentences and words, but also about linking new content to their prior knowledge, which in turn facilitates the integration of information extracted from reading. Summarization is the most difficult and weakest skill for elementary school students. Teaching summarization strategies helps students with reading comprehension and encourages them to self-monitor and adjust their learning. This paper is about a research on teaching summarization strategy in the fifth and sixth grade and its effect. The teaching activities were planned based on the summarization-related instructional materials in the fifth and sixth grade. Two elementary schools located in Taipei City were taken as the research objects. During the research, the team recorded students' difficulties in summarization, collected teaching-and-learning feedback sheets and compared the difference between pretest and posttest. Based on the research findings, the paper reflects on the teaching of reading summarization strategies and provides suggestions for improvement.