With the continuous development of information technology, the internet has become an indispensable tool in modern society. However, its widespread use has also brought about numerous psychological health issues, particularly internet addiction and feelings of loneliness. This article explores the bidirectional relationship between internet addiction and loneliness from a psychological perspective. By analyzing recent research, the article highlights how internet addiction exacerbates feelings of loneliness and how loneliness can serve as a trigger for internet addiction. Finally, drawing on the latest psychological theories, the article presents the psychological mechanisms underlying the relationship between the two and offers recommendations for future research directions and intervention strategies.