<p>With the proliferation of smartphones and the development of the internet, excessive smartphone use has become widespread among college students, making the issue of smartphone addiction increasingly severe. Invalidating environment may be a key influencing factor in increasing adolescents’ smartphone addiction. Existing studies have not directly explored the effects of the invalidating environment on smartphone addiction and its underlying mechanisms. Guided by Interaction of Person-Affect-Cognition-Execution model (I-PACE), this study examined the relationship between invalidating environment and college students’ smartphone addiction using a serial mediation model that included regulatory emotional self-efficacy and psychache as hypothesized mediators. Using convenience sampling, 493 college students (69% female, 31% male; Mage = 19.52 years, SD = 1.88) were recruited to complete four standardized questionnaires—the Invalidating Childhood Environment Scale, the Mobile Phone Addiction Tendency Scale, the Regulatory Emotional Self-Efficacy Scale, and the Psychache Scale. Data were collected face-to-face via an online survey platform, with researchers present throughout to provide supervision and guidance. The results revealed that invalidating environment positively predicted smartphone addiction among college students. Both regulatory emotional self-efficacy and psychache independently mediated this relationship, and together, they also formed a significant sequential pathway, where lower regulatory emotional self-efficacy was associated with greater psychache, which in turn predicted higher levels of smartphone addiction. This study is the first to identify invalidating environment as a key predictor of smartphone addiction among college students, particularly within the context of Chinese culture, where emotional expression in families tends to be more restrained. The findings offer potential guidance for the development of prevention and intervention strategies targeting smartphone addiction.</p>