Childhood psychological abuse (CPA) is highly associated with depression among college students. However, the underlying mechanisms between these variables need further exploration. This study aims to investigate internet addiction as a mediating factor and alexithymia and its different dimensions as moderating factors, to further complement the psychological mechanisms between CPA and depression among college students. A self-report survey was conducted on 625 college students from two universities in Hunan Province, China. The survey included CPA, internet addiction, alexithymia, and depression. Descriptive and correlational analyses were performed on these variables, and a moderated mediation model was constructed. CPA is positively correlated with depression, internet addiction, and alexithymia among college students. Internet addiction partially mediates the relationship between CPA and depression among college students, while alexithymia enhances the relationship between CPA and internet addiction as well as depression among college students. The moderating effect of the different dimensions of alexithymia is inconsistent, with the modulation effect of difficulty in identifying feelings being the strongest. This study further elucidates the psychological mechanisms between CPA and depression among college students. Internet addiction serves as a mediating factor, while alexithymia may strengthen the relationship between CPA and internet addiction, as well as between CPA and depression.