Abstract: Objective To explore the relationship among transition shock, perceived organizational support and professional identification of new nurses in tertiary hospital, and provide some reference for helping the new nurses to pass through the transition period smoothly. Methods A total of 421 qualified new nurses were recruited from tertiary hospitals of Zhejiang province between January and June, 2019 by convenience sampling method. The Transition Shock of Newly Graduated Nurses Scale, Professional Identification Scale for Nurses and Perceived Organizational Support Scale for Nurses were used in the investigation. The SPSS 22.0 was used for data analysis, and the Amos 17.0 was used for mediating effects test. Results The score of transition shock was 100.57±13.64, with the scoring rate of 74.5%, and the subscale scoring rates from high to low were physical aspect, knowledge/skills aspect, sociocultural and development aspect, psychological aspect. The score of professional identification was 2.81±0.61, with the subscale scores from high to low were career self-concept, sense of career gain and sense of career motivation. The score of perceived organizational support was 3.19±0.53, with the subscale scores from high to low were emotional support and instrumental support. A significant correlation was found between the transition shock, professional identification and perceived organizational support(all P<0.01). Mediating effect analyses revealed that transition shock exerted a partial mediating effect between perceived organizational support and professional identification, with the mediating effect of 43.3%. Conclusion Nursing managers should strengthen their support to new nurses according to the hospital reality, improve their perceived organizational support, take targeted measures to help them through the transition period in order to strengthen their professional identification and stabilize the clinical nursing team.