Becoming an effective reader requires cultivating habits of extensive reading and acquiring efficient reading strategies. This study investigated the reading comprehension performance of learners with three different reading summary strategies: "cooperative mind maps," "co-text," and "individual mind maps." Participants were 272 high school students. The result showed that the "cooperative mind map group" significantly outperformed the “individual mind map group,” indicating that the group discussion process is essential to build deeper comprehensive understanding of the reading material, given the same condition of using the mind mapping tool to write summaries. Our major results showed that combining group discussion with a mind map as a visual summary writing tool is the most beneficial approach for improving students' reading performance. In addition, through the summary construction process using the mind mapping tool rather than a simple text tool, students could better identify important concepts, think about relationships and hierarchies between concepts, and thus developed a better ability to organize and understand the reading content.