Objective:To explore the causes of high noise exposure in PICU, and to provide reference for formulating effective intervention measures to improve the status of noise exposure.Methods:With phenomenological method, eleven nurses of Xinhua Hospital, Shanghai Jiaotong University School of Medicine from August to September 2020 were enrolled by purposive sampling method, and joined face-to-face and semi-structured interviews with researchers. Interview data were analyzed by Colaizzi 7-step analysis method.Results:Four themes were extracted, including the characteristics of PICU, difficulty in equipment alarm management, the crying of children which was difficult to appease, and the low level of knowledge, attitude and practice of noise management of medical staff.Conclusions:High noise exposure of PICU is caused by many reasons. Researchers and managers can optimize the equipment alarm management, implement ideal analgesia and sedation and humanistic care, and carry out noise management training to improve the noise exposure in PICU and the quality of clinical nursing.