Aim: To explore the effects of demographic characteristics, mental workload, and Adversity quotient (AQ) on the job engagement of nurses in East China. Design: A quantitative and cross‐sectional study. Method: The survey collected questionnaire data on mental workload, adversity quotient, and job engagement from 473 nurses selected working in 12 Grade‐A tertiary hospitals based on informed consent in East China between July 2020 and March 2021. Results: The total score of mental workload was 78.24 ± 11.65, the adversity quotient score was 128.26 ± 15.84, job engagement score was 42.32 ± 7.79. Job engagement has a remarkable positive correlation with adversity quotient (r = 0.613, p<0.001), and a negative correlation with mental workload (r = −0.499, p<0.001). Mental workload has an apparent negative correlation with adversity quotient (r = −0.291, p<0.001). Labor‐management relationship with current organization, department, study to get a degree or diploma in spare time, attitude towards a career in Nursing, attitude towards the current career position, satisfaction with marriage, social support, load feelings, self‐assessment, control, and endurance could predict 70.9% of job engagement of nurses. Conclusions: The mental workload of nurses was higher, the AQ was at a medium level, and the job engagement of nurses was also slightly higher. Labor‐management relationship with current organization, department, study to get a degree or diploma in spare time, attitude towards a career in Nursing, attitude towards the current career position, satisfaction with marriage, social support, load feelings, self‐assessment, control, and endurance had predictive effects on nurses' job engagement. It is necessary to take a variety of measures according to the social‐demographic characteristics, improve the adversity quotient, and evaluate the mental workload correctly, to improve the job engagement of nurses. Impact: The epidemic situation and other emergencies make the work pressure of nurses in Grade‐A tertiary hospitals increase suddenly. It should pay attention to the influence of different demographic factors, and pay attention to the correct guidance of work demand‐mental workload, as well as the cultivation, and improvement of job resource‐AQ, which can improve the job engagement of nurses to some extent. Patient or Public Contribution: No patient or public contribution. [ABSTRACT FROM AUTHOR]