With the widespread use of smartphones, smartphone use before bedtime has become a common behavior among college students, closely linked to their sleep quality issues. This review aims to systematically synthesize existing research to explore the impact of smartphone use before bedtime on college students’ sleep quality and its underlying mechanisms, and to propose targeted intervention strategies. A comprehensive analysis of relevant literature shows that sleep problems such as delayed sleep onset, insufficient sleep duration, and poor sleep quality are prevalent among Chinese college students. There is a significant negative correlation between smartphone use before sleep and sleep quality: the blue light emitted by smartphone screens inhibits melatonin secretion and disrupts circadian rhythms; continuous psychological arousal and cognitive stimulation from new media content, combined with “revenge bedtime procrastination” and sleep delay caused by poor self-control, collectively form a complex pathway that impairs sleep quality. To address these issues, interventions should be implemented at both the individual and school levels. College students should maintain regular routines, avoid electronic devices before bedtime, and optimize sleep environments; colleges and universities need to construct a multi-dimensional sleep health support system through campus cultural activities, dormitory management, and health education. This review emphasizes the importance of reducing smartphone use before bedtime and building a multi-stakeholder collaborative intervention system, which is crucial for helping college students develop healthy sleep habits and promoting their academic progress and physical and mental well-being.