Reading has been regarded as a medium for learning science, revealing the importance of enhancing learners' reading competence in science education. The critical features of science texts are their multiple representations, such as text and visual elements, which assist the representation of science concepts. A multimedia learning environment can present relevant materials in various formats and help students to process the materials in meaningful ways, for example, by integrating learning materials with relevant prior concepts, and organizing them into a consistent and coherent cognitive structure. However, some issues with multimedia instructional design have been proposed, such as students' cognitive load and learning motivations. In this study, an augmented reality-based science learning system was developed based on the contiguity principle of multimedia learning in order to promote students' science learning. Moreover, an experiment was conducted on a natural science course in an elementary school to assess the effectiveness of the implemented system on students' learning. The experimental results display that the students learning with this approach found made significant gains in their learning achievements and motivations compared to those learning science with conventional multimedia science learning; moreover, their perceptions of extraneous cognitive load were significantly reduced during the learning activity.