This study investigated the effects of music combined with heartbeat sounds played through stuffed animals for 4 weeks on children’s emotional-regulation ability, parent-child attachment, and parenting stress. We randomly allocated 63 healthy 5- to 6-year-olds (33 boys and 30 girls) to a music training (n = 31) or a waiting-list control (n = 32) group. Each training-group subject was given a soft stuffed animal with an inbuilt speaker. For 4 weeks, subjects listened to four types of music combined with heartbeat sounds (two children’s songs and two instrumental pieces) daily. Pre- and post-training assessments included ratings from parent reports. The outcome measures were Emotion Regulation Checklist, Inventory of Parents and Peer Attachment, and Parenting Stress Index–Short Form. Results indicated an improvement in adaptive emotion regulation in children, parent-child attachment, and positive parent-child interactions in the training group. We discussed the implications of the use of music combined with heartbeat sounds on the improvement of children’s emotional regulation and parent-child relationship.