Emotional design refers to the use of a series of design features, such as the design layout, color, and sound in multimedia environments, to increase the attractiveness of learning materials, induce learners' positive emotions and promote multimedia learning. It has not yet reached a consensus whether visual emotional design can induce learners' positive emotions, increase learners' mental effort, and improve retention and transfer tests. The cognitive theory of multimedia learning holds that we can process visual information through visual channel and audio information through aural channel. Previous studies only examined the effects of visual emotional design on multimedia learning. Can aural emotional design also increase the attractiveness of learning materials, induce learners' positive emotions and promote multimedia learning? In this study, we used two experiments to examine the impact of visual and aural emotional design on multimedia learning, respectively. In experiment 1, a total of 100 participants were recruited and 60 subjects' data were analyzed. The experimental material was a Flash animation, "How the Immune System Works", combined with narration. The learning materials of the visual emotional design group used bright colors (such as orange, blue), combined with round and anthropomorphic design. The learning materials of the neutral design group used black, white and gray colors, and the cells were designed as rectangles. The results suggested that the positive emotions and the retention scores of the emotional design group were significantly higher than those of the neutral design group, but there was no significant difference in cognitive load or transfer test between the two groups. In experiment 2, a total of 176 participants were recruited, and 93 subjects' data were analyzed. We used the learning materials of the neutral design group. As for the narration materials, we used the Pitch-Synchronous Overlap Add of Praat software to increase 0.5 Equivalent Rectangular Bandwidths (ERB) of the raw pitch so to form a treble pitch; similarly, the original pitch was reduced by 0.5ERB to form a bass pitch. Results indicated that positive emotions, germane cognitive load, retention test scores of the bass group were significantly higher than those of the raw pitch group; retention and transfer test scores of the bass group were significantly higher than those of the treble pitch group; germane cognitive load of the treble group were significantly higher than those of the raw pitch group; the three pitch groups did not differ from each other in other aspects. This study shows that both visual and aural emotional design can significantly facilitate and improve multimedia learning outcomes. The corroboration of the effects of aural emotional design on multimedia learning has contributed to the existing research, in which previous researchers only optimized learning materials through visual emotional design. Thus we expanded the definition of emotional design in multimedia learning to include aural emotional design. In this study, we examined visual and aural emotional design separately. However, according to the channel principle of multimedia learning, visual and aural information presented at the same time is better than information presented separately. Therefore, future researchers are encouraged to test the relevant research question.