Objective:To explore the real experience of developing self-consciousness, self-discovery, self-identity crisis and self-cognition improvement of young cancer patients from the initial stage of diagnosis, and to provide reference for medical staff to construct the intervention mode of psychosocial support.Methods:Using phenomenological method in qualitative research, 14 young cancer patients aged 18-25 years from April 2019 to August 2020 in Jiangsu Cancer Hospital were interviewed in semi-structured way separately at three time points: initial diagnosis, 6 months after diagnosis and 12 months after diagnosis. 7-step Colaizzi analysis was used to analyze the data.Results:Three themes were extracted as following. The dilemma of self-cognition, self-identity biases and the exploration of self-identity.Conclusions:Attention should be paid to the psychological problems of young cancer patients at all stages, and meet the needs of patients to talk, cooperate with professional psychotherapists, encourage patients to recognize themselves, tap the inner positive power, so as to improve their sense of self-identity.