Helping children with autism gain a better grasp of vocabulary is an important way to improve their language skills. Information that incorporates emotional prosodies provide richer semantics and context and may be more conducive to vocabulary acquisition in children with autism. This study aimed to explore the facilitating effect of positive emotional prosody on vocabulary acquisition with children with autism. A total of 12 children with autism received interventions with neutral and positive emotional prosodies. The results revealed that vocabulary learned in positive emotional prosodies was more effective than neutral prosodies. The differences in the learning effects of emotional prosodies on part of speech were not significant. However, in children with higher autism severity, neutral prosodies led to diminished expressive vocabulary performance. This study improved vocabulary comprehension and language skills of children with autism through emotional prosody intervention and tentatively revealed the role of lexicality in this.