Childhood abuse is a significant risk factor for suicidal ideation. However, the underlying mediation mechanism necessitates further exploration. This study investigated the mediating role of core self-evaluation and negative emotions in the relationship between childhood abuse and suicide ideation in young adults. A sample of 3103 college students from 11 universities across 8 provinces in China was analyzed. Childhood abuse, core self-evaluation, negative emotions, and suicidal ideation were assessed using the Childhood Trauma Questionnaire (CTQ-CF), Core Self-Evaluation Scale, Affect Scale, and Beck Suicidal Ideation Scale (BSI-CV), respectively. Data analysis was conducted using SPSS 19.0 and SPSS Macro Process. We found that high scores for childhood abuse were associated with elevated levels of suicidal ideation, whereas low scores for core self-evaluation were closely linked to heightened levels of negative emotions and suicidal ideation. Furthermore, core self-evaluation and negative emotions mediated the relationship between childhood abuse and suicidal ideation through three significant paths. The results demonstrate that childhood abuse can directly impact suicidal ideation in young adulthood and indirectly influence suicidal ideation by affecting core self-evaluation and negative emotions. They suggest that addressing core self-evaluation and negative emotions in individuals who have experienced childhood abuse may help prevent or treat suicidal ideation.