Background: Studies have shown that poor sleep could result in many unpleasant consequences and is prevalent in nurses. Considering the fact of high stress, overwhelming workload and many night shifts in the emergency department in China, this study aimed to evaluate the current status of emergency nurses' sleep quality in public hospitals in Shandong, China and explored its influencing factors. Methods: A self-administered questionnaire incorporating the Job Content Questionnaire and Pittsburgh Sleep Quality Index (PSQI) was conducted among 4856 emergency nurses in five randomly selected city emergency command systems in Shandong, China. The association of potential influencing factors, including occupational, psychosocial and individual factors, with poor sleep (PSQI> 5) was quantified by multivariate logistic regression analysis. Results: The average PSQI score of 4730 emergency nurses in public hospitals was 8.2 ± 3.9, including 3114 (65.8%) subjects with PSQI > 5 and 2905 (61.4%) > 8; these figures were found highest for 337 emergency nurses in 14 tertiary hospitals with 11.8 ± 4.3, 257 (76.3%) and 232 (68.8%), followed by 1044 emergency nurses in 43 secondary hospitals with 9.5 ± 3.9, 725 (69.4%) and 675 (64.7%) and 3349 emergency nurses in 167 primary hospitals with 7.4 ± 3.5, 2132 (63.7%) and 1998 (59.7%). The following factors were associated with poor sleep: hospital level (tertiary vs. primary, secondary vs. primary), female sex, less of exercise, long work hours per week, many patients in the charge of at night, high monthly night shift frequency (4-6 vs. never, ≥7 vs. never) and high occupational stress. Conclusions: The sleep quality of emergency nurses in public hospitals in China was poor, especially in tertiary hospitals. Many factors as listed above, especially occupational stress, night shift taking and workload at night, should be considered when improving emergency nurses' sleep quality.