Objective To explore the mediating role of transition shock among newly graduated nurses between horizontal violence and turnover intention and the moderating role of adversity quotient. Methods A total of 1,019 newly graduated nurses from 80 tertiary hospitals in 25 provinces and cities were selected by convenience sampling method from November to December 2023, and they were surveyed using the general demographic questionnaire, the Negative Acts Questionnaire, the Transition Shock of Newly Graduated Nurses Scale, the Self-evaluation Scale for Nurses′ Adversity Quotient and the Turnover Intention Questionnaire (TIQ). Results The scores of newly graduated nurses′ horizontal violence, transition shock, adversity quotient, and turnover intention were 20.00 (19.00, 23.00), (88.52±21.50), (94.91±14.58), and (14.64±4.01) respectively. Newly graduated nurses′ horizontal violence positively predicted turnover intention (β=0.094，P<0.05), and transition shock partially mediated between horizontal violence and turnover intention, accounting for 58.59% of the total effect. Adversity quotient moderated the mediating effect of transition shock (β=0.104, P<0.05). Conclusion Newly graduated nurses′ transition shock has a mediating role between horizontal violence and turnover intention, and the adversity quotient moderates its mediating role. It is recommended that nursing managers strengthen the management of horizontal violence, give support and tolerance to newly graduated nurses, and improve their ability to resist adversity in order to alleviate their transition shock, promote role change, and stabilize the nursing workforce.