Tracking individual reading behaviors is a difficult task, as is carrying out real-time recording and analysis throughout the reading process, but these aims are worth pursuing. In this study, the reading rate is adopted as an indicator to identify different reading behaviors and comprehension outcomes. A reading rate tracking technique is thus developed with an Interactive E-book Learning System (IELS), and this study examines whether the reading rate detected by this system can properly reflect the actual reading behaviors and comprehension outcomes of users. A total of 500 quantitative records were collected from the reading profiles of 43 fifth-grade students, separated into two groups for oral and silent reading behaviors, and then analyzed to reveal the reading rates accounting for specific reading behaviors and comprehension outcomes. Our findings indicate that the reading rate can accurately reflect students' reading behaviors. In addition, a somewhat positive correlation between reading rates and comprehension outcomes was only found in the silent reading group. By using the technique presented in this work, the reading behaviors related to e-books can be easily interpreted based on the reading rate over time throughout the reading process, something that is much more difficult when using printed books. Based on the results of this work, it is anticipated that educators can get better insights into students' behaviors with regard to reading, so as to deliver more personalized and effective instruction.