Objective To explore the emergency nurses′ cognition in the protection of patients′ privacy and its influencing factors, and provide guidance and references for privacy protection of clinical patients. Methods Self-designed questionnaire was used to investigate 982 emergency nurses of some secondary and tertiary hospitals in Shanghai from October to December 2015. Investigative contents includes: the cognition of nursing staff in patients′ privacy information, the cognition in privacy body parts of patients, influencing factors that affect the cognition of nurses in patients′ privacy. Results For the cognition of nursing staff in patients′ privacy, the top 5 patients′ privacy contents among 11 privacy information contents were : patients′ ID number (94.70%), family address (94.70%), phone number (92.57%), medical history (91.85%) and Spiritual and psychological activities (90.02%). The top 5 privacy body parts of patients among 9 privacy body parts were: perineum(97.15%), breast (95.52%), buttock (94.81%), abdomen (79.84%) and thigh (77.60%). There was no significant difference in cognition of nurses in the protection of patients′ privacy between secondary hospitals and tertiary hospitals, specialized hospitals and general hospitals, unmarried nurses and married nurses, senior nurses and junior nurses (P>0.05). There was no significant difference in cognition of nurses in the protection of patients′ privacy between nurses with different marital status and different qualification (P>0.05). Cognition difference in privacy protection of patients′ head and neck between unmarried nurses and married nurses was significant (χ2=8.249, P=0.041). Cognition difference in privacy protection of patients′ head and neck, arms and legs between senior nurses and junior nurses was significant (χ2=9.893, 15.879, 11.329; P<0.05). The present status of nurses active action in patients privacy protection, was positively correlated to the age, professional title, working years, understanding of the patients privacy knowledge, participation in the protection of privacy training and willness of protecting patients′ privacy information (r=0.084, 0.086, 0.109, 0.295, 0.391, 0.451; P<0.05). Conclusions We should strengthen the training related to patients privacy protection knowledge for emergency nurses; enhance the understanding of knowledge related to patients′ privacy, and carry out the nursing measures to protect the privacy of patients, so as to promote harmonious doctor-patient relationship. Key words: Nursing staff; Questionnaires; Privacy; Patients; Emergency department