Background <p>This study aimed to identify factors associated with professional identity among nursing interns in China. Such evidence may help inform educational and clinical mentoring strategies to cultivate and strengthen professional identity during clinical internship, and may contribute to future retention among nursing interns, thereby supporting nursing workforce stability and improving the quality of nursing care.</p> Methods <p>CNKI, Wanfang, VIP, the Chinese Biomedical Literature Database, PubMed, Web of Science, Embase, CINAHL and the Cochrane Library were searched from database inception to 20 January 2026. Cross-sectional studies involving nursing interns in China and reporting professional identity and its associated factors were included. Methodological quality was assessed using the quality assessment criteria for cross-sectional studies recommended by the Agency for Healthcare Research and Quality. Meta-analysis was performed using RevMan 5.4, with the correlation coefficient r used as the effect size.</p> Results <p>A total of 48 studies were included, comprising 41 Chinese-language and seven English-language publications. Overall, 42 factors associated with professional identity were identified; 12 were included in the meta-analysis and 30 were synthesised descriptively. The meta-analysis showed that humanistic caring ability (<i>r</i> = 0.77, 95% CI: 0.48–0.91), medical narrative competence (<i>r</i> = 0.64, 95% CI: 0.60–0.69), professional self-efficacy (<i>r</i> = 0.62, 95% CI: 0.49–0.72), perceived professional benefit (<i>r</i> = 0.62, 95% CI: 0.57–0.66), clinical learning environment (<i>r</i> = 0.53, 95% CI: 0.18–0.77), psychological resilience (<i>r</i> = 0.52, 95% CI: 0.39–0.62), social support (<i>r</i> = 0.52, 95% CI: 0.34–0.66), perception of hospital caring climate (<i>r</i> = 0.45, 95% CI: 0.31–0.57), and perceived teacher caring (<i>r</i> = 0.36, 95% CI: 0.22–0.50) were positively associated with professional identity. Role stress (<i>r</i> = -0.32, 95% CI: -0.38 to -0.25) and anxiety (<i>r</i> = -0.14, 95% CI: -0.19 to -0.10) were negatively associated with professional identity. The association between clinical practice behaviour and professional identity was not statistically significant (<i>r</i> = 0.41, 95% CI: -0.03 to 0.73).</p> Conclusion <p>This study showed that professional identity among nursing interns in China was associated with multiple factors. Humanistic caring ability, clinical learning environment, psychological resilience, professional self-efficacy, perceived teacher caring, hospital caring climate, medical narrative competence, perceived professional benefit and social support were associated with higher professional identity, whereas role stress and anxiety were associated with lower professional identity. The association between clinical practice behaviour and professional identity remained inconclusive. Nursing colleges and internship hospitals should support the development of professional identity among nursing interns by optimising the clinical learning environment, strengthening clinical mentoring support, enhancing psychological resources and reducing negative emotional experiences.</p>