This research aims to understand the effectiveness of training by playing on four key aspects to develop the interaction between mother and children in early childhood (children aged 3-6 years). The four key aspects of the mother-child interaction are affection, responsiveness, encouragement, and teaching (Roggman et al., 2013). AB design was applied to 11 mother-child dyads as participants. The mothers were provided with 4-day training for a total of 15 hours. The training materials covered the characteristic of children in early childhood, play, and mother-child interaction. Data were analyzed with a combination of qualitative and quantitative methods and t-test statistics. The mother-child interaction was observed and measured using Parenting Interactions with Children: Checklist of Observations Linked to Outcomes (PICCOLO) (Roggman et al., 2013). Statistical results show a significant difference between motherchild interaction scores before and after the training on the four key aspects (t = −3.339, p = 0,008 ≤ 0.05). Hence, the training on the four key aspects effectively develops the interaction between mother and children in early childhood.