Objective To explore the influence of preferred contract-altering system on contracted nurses to provide reference for stabilizing a team of high quality nursing.Method A scale on effort-reward unfairness(ERI)was used to investigate the ERI conditions among 348 contracted nurses before and after the enforcement of preferred contract-altering system.Results The scores on satisfaction with nursing work and the security in nursing work after the enforcement of the system were higher than before the enforcement(P<0.01).The ratio between effort and reward after the enforcement was lower than before the enforcement(P<0.01). Conclusions The preferred contract-altering system may enhance the job security and sense of belonging.It may decrease the ERI condition among contracted nurses,which are beneficial for stabilizing the nurses team,retaining talents and increasing the group’s competitiveness and vigour.