Objective: To gain an in depth understanding of the cognitive appraisal of middle school students with mental illness after experiencing childhood trauma, so as to provide a reference for the development of effective interventions. Methods: From March to September in 2023, 21 middle school students with childhood trauma experiences and mental illnesses were selected from outpatient and inpatient departments through purposive sampling in a tertiary grade A psychiatric hospital in Wuhan. Semistructured interviews were conducted and the seven steps of Colaizzi phenomenology were used to analyze the data and extract themes. Results: A total of 3 themes and 11 subthemes were extracted:insufficient awareness of childhood trauma (lack of selfawareness, lack of awareness of primary caregivers), multiple hurtful experiences after experiencing childhood trauma (complex negative affective experiences, multiple physical discomfort, pessimistic attitudes toward life, social impairment, and academic impairment), and influences on childhood trauma experiences (personality traits, inappropriate personal coping styles, poor upbringing environment, and difficulty in obtaining social support). Conclusions Middle school students with mental illnesses and their caregivers generally lack knowledge about childhood trauma, which brings widespread harm and are affected by multiple factors. It should jointly strengthen the popularization of scientific knowledge, intervene in a timely manner, and thereby reduce the adverse consequences of childhood trauma experiences.