With advancements in interactive technologies, social robots are increasingly being utilized in educational settings. This study examined the effects of voice enthusiasm in social robots on children’s learning emotion and learning performance. A total of 92 fifth- and sixth-grade students participated in a between-subjects experimental design. The children's emotional responses were assessed using the Pleasure-Arousal-Dominance (PAD) model. The results indicated that the social robot's vocal enthusiasm had a significant effect on children's learning emotions. Specifically, the children exhibited a clear preference for interacting with the social robot that demonstrated an enthusiastic vocal tone, suggesting that vocal enthusiasm positively influenced their emotional engagement during the learning process. Moreover, voice enthusiasm in the social robot significantly affect learning performance (knowledge retention/transfer). These findings highlight the potential of incorporating vocal expressiveness into social robots and interactive instructional materials to foster more engaging and effective learning experiences for children.