Objectives This study suggests Behavioral Activation System(BAS), Behavioral Inhibition System(BIS), Maladaptive Cognitive Emotion Regulation Strategies as the cause of Smartphone addiction and attempted to examine the correlation of these. Moreover, this study is to prove BAS and BIS affects Smartphone addiction through Maladaptive Cognitive Emotion Regulation Strategies.
 Methods The total of 464 high school students who are vulnerable to behavioral addiction participated in measuring Smartphone addiction using Korean version BAS/BIS, Cognitive Emotion Regulation Questionnaire(K-CERQ) and smartphone addiction self-diagnosis scales.
 Results First, BAS/BIS and Maladaptive Cognitive Emotion Regulation Strategies and smartphone addiction showed significant proportional correlation. Second, BAS/BIS and Maladaptive Cognitive Emotion Regulation Strategies explain clearly on the smartphone addiction. Last, Maladaptive Cognitive Emotion Regulation Strategies fully mediates between BAS and smartphone addiction which means BAS respectively does not cause direct effect to smartphone addiction but causes indirect effects. Maladaptive Cognitive Emotion Regulation Strategies partially mediates between BIS and smartphone addiction which means BIS respectively does not cause direct effect to smartphone addiction but causes indirect effects. The outcome of this study implies that the BIS directly affects smartphone addiction and also it affects indirectly through Maladaptive Cognitive Emotion Regulation Strategies.
 Conclusions The results of this study verified the mediating effect of the maladaptive cognitive emotion regulation strategy in relation to the recent serious problem of smartphone addiction among adolescents, and highlighted its importance.