Objective To investigate the current status of self-disclosure, professional identity, and humanistic care ability among nursing undergraduates, to explore the mediating effect of professional identity on the relationship between self-disclosure and humanistic care ability, and to provide a basis for improving the humanistic care ability of nursing undergraduates.Methods A convenience sampling method was used to select 430 nursing undergraduates.Data were collected using a general information questionnaire, the Caring Ability Inventory (CAI), the Professional Identity Questionnaire for Nurse Students (PIQNS), and the Distress Disclosure Index (DDl).Multiple linear regression analysis was employed to identify factors influencing the humanistic care ability of nursing undergraduates, and a structural equation model was constructed to verify the mediating effect of professional identity in the relationship between self-disclosure and humanistic care ability.Results The score of humanistic care ability among nursing undergraduates was (175.98±20.01) points. Self-disclosure, professional identity, and humanistic care ability among nursing undergraduates were positively correlated (all P＜0.05).Professional identity played a partial mediating role between self-disclosure and humanistic care ability (accounting for 51.6% of the total effect).Conclusion The humanistic care ability of nursing undergra-duates is at a mode-rate level.Self-disclosure can directly and positively predict humanistic care ability, and can also indirectly affect humanistic care ability through the mediating role of professional identity.Nursing educators can enhance the level of self-disclosure and professional identity among nursing undergraduates by analyzing students′ personality characteristics and strengthening course ideology and career education, thereby improving their humanistic care ability.