As mobile devices and the internet are common nowadays, and mobile communication technology and image analysis technology are developing, augmented reality (AR) is rapidly evolving and gradually being widely used in many fields. The study used AR application as a new type of multimedia teaching tool in science instruction. The purpose of the study aimed to investigate the influence of using AR into science instruction for students' learning motivation and academic achievement. The experiment adopted a pretest-posttest design on 49 ninth grade students. Before and after the experiment, the Electromagnetism achievement test and ARCS motivation questionnaire were used as evaluation tools. The result showed that using AR on science instruction can improve students' learning motivation compared with traditional instruction. In particular, there is a significant difference in improving the attention of learning motivation. However, there is no improvement effect and no significant difference in academic achievement between using AR and traditional science instruction.