In early education, reading difficulties can lead to negative outcomes. Augmented reality (AR) storybooks combine the benefits of e-books and print books, significantly aiding children's reading skills and gaining recognition from scholars and educators. However, the existing AR storybooks often overlook the design of interactive features, which may explain the inconsistent findings in research on their impact. This study aims to embed interactive tasks into AR storybooks and investigate their effects on children's reading engagement, story retelling, and reading comprehension. In total, 40 children aged eight to ten years were invited to participate in the reading activity. They were randomly assigned to an experimental group and a control group. The experimental group used AR storybooks that included interactive tasks, requiring them to complete various activities during reading. The control group used AR storybooks without interactive tasks, which provided multisensory experiences. Throughout the activity, researchers observed each child's reading engagement and completed a reading engagement assessment form. At the end of the activity, all children completed story retelling and reading comprehension tests. Finally, both groups of children participated in semistructured interviews for cross validation. The study found that children in the experimental group showed significantly higher levels of reading engagement, story retelling, and reading comprehension than children in the control group. While multimedia elements in AR storybooks can increase children's reading engagement, a large part of that engagement is driven by children's focus on AR elements. However, interactive tasks shift children's engagement more toward the story content. We also discovered that interactive tasks are a key factor in encouraging children to think actively and serve as an effective strategy for guiding them to focus on the main issues in the story. In addition, the strategy search decision feedback within the interactive tasks greatly aids children in understanding and remembering the story.