This purpose of this study is to find out the relationship among Mother s smartphone addiction, Maternal play Particiation, Children s overindulgence tendency. Participants were 263 mothers with children between 2 and 5. in Seoul and Gyeong-gi province. The major findings were as follows: First, it is statistically significantly different according to how frequently mother uses smart media, how mother restricts children s use of digital media and whether mother and children use digital media together or not. Second, the total score of mother s smartphone addiction tendency and one sub component, morbid immersion positively related to children s overindulgence tendency in smart devices, mother s play participation negatively related to children s overindulgence tendency in smart devices and mother s smartphone addiction tendency negatively related to mother s play participation. And lastly, mother s play participation partially mediated the relationship between mother s smartphone addiction tendency and children s overindulgence tendency in smart devices.