Objective To analyze the relationship among nurses′ organizational support, psychological security and job engagement, and to provide basis for measures aiming at improving nurses′ engagement and nursing management. Methods The general data questionnaire, Organizational Support Scale, Psychological Security Scale and Gallup Q12 questionnaire were used to survey 414 nurses in a 3A hospital in Tianjin. Results The total score of engagement was （2.09±0.38）, being at medium level; organizational support score was （3.19±0.31）, and psychological security score was （3.42±0.45）.There were significant positive correlations between engagement or organizational support and psychological security （P＜0.05,P＜0.01）, likewise between engagement and organizational support （P＜0.01）.Psychological security exerted a mediating effect of 0.34 in the relationship between organizational support and engagement. Psychological security and organizational support together explained 21% of the total variation of engagement. Conclusion Nurses engagement was at medium level.Nursing managers should create a good environment favoring organizational support and give nurses more emotional support, in an effort to improve nurses′ psychological security and job engagement.