This study examined the impact of e-book interactivity design on the learning of Chinese characters by fourth graders (10-year-old children). This study was guided by two main questions: (1) Are there any differences in achievements (Chinese character writing, lexical comprehension, and lexical usage) between groups of young learners who read e-books with different interactivity levels? and (2) Are there any differences in motivation (attention, confidence, relevance, and satisfaction) between groups of young learners who read e-books with different interactivity levels? This study was an experimental design where the independent variable was the interactivity design of digital books. A sample of 99 fourth graders participated in the study and participants were randomly assigned into these two groups, with one group reading an e-book with a low level of interactivity (pace-control only) and the other reading an e-book with a high level of interactivity (sequence- and media-control). Participants were asked to complete a pre-test first, and then they read their assigned e-books for 30 minutes. After they finished reading, they were given a post-test. The results showed a reverse interactivity effect, that is, the group reading the e-book with the low level of interactivity (pace-control only) performed significantly better in Chinese character writing, attention, and satisfaction. This might be due to young learners' limited cognitive capacity and processing ability for learning with hypermedia. This study aims to expand on existing theories on interactive learning for young learners and serves as a reference for elementary school teachers and e-book publishers.