PURPOSE: Ovarian cancer can have a significant psychological impact on young and middle-aged patients who are often prone to recurring changes in mood that can lead to rumination. This phenomenological qualitative study aimed to explore rumination in young and middle-aged ovarian cancer survivors. METHODS: From August to November 2023, 21 young and middle-aged ovarian cancer survivors who were treated at a tertiary general hospital in Changsha, Hunan Province, China were selected using purposive sampling. In-depth semi-structured interviews were conducted using phenomenological research methods; interview data were analyzed according to the Colaizzi 7-step analysis method. RESULTS: Rumination among young and middle-aged ovarian cancer survivors was summarized into four themes and 12 subthemes: uncontrollable response (unstoppable depression, sustained concerns, psychosomatic symptoms), persistent frustration (stigma, consciousness of self-guilt, social avoidance), recurring anxiety (anxiety about death, cancer recurrence, loss of function), and adaptive adjustment (distancing from emotional black holes, clarifying the value of life, and engaging in meaningful action). CONCLUSION: Rumination is common among young and middle-aged ovarian cancer survivors. They experience uncontrollable responses, persistent frustration, recurring anxiety, and adaptive adjustment. These results can provide a reference for healthcare professionals to develop targeted intervention strategies. IMPLICATIONS: This study revealed the content and experiences of rumination among young and middle-aged ovarian cancer survivors, providing theoretical support for intervention development. Mindfulness-based therapies may be useful in helping patients strengthen their psychological coping, and combining social resources to provide patients with comprehensive support may help reduce their negative emotions and improve quality of life.