The purpose of the study was to prove the effects of ACT based stress management program on decentering, ego-resilience and job stress coping by applying the program to social worker.In order to achieve the purpose, The final 16 persons who were recruited to social welfare organizations in busan by promoting the stress management program for social workers were assigned to 8 experimental groups and 8 control groups respectively., and then ACT based stress management program was put into practice to the experimental group while no measure was taken to the control group.To examine the effects of the program, pretest and posttest were conducted to the two groups on decentering, ego-reilience, and job stress coping, and SPSS/WIN+23.0 statistics program was used to get the average and standard deviation on the respective level. So as to verify the gap between the two groups, analysis of covariance (ANCOVA) on the scores of the posttest of the two groups were put into practice by regarding the scores of the pretests of both groups as covariate variable. In order to supplement the quantitative study of statistical analysis, the content analysis was performed.The results of the study by this study procedure are as follow.First, After participating in the stress management program, the experimental group became better in decentering than the control group who didn't take part in it.Second, After participating in the stress management program, the experimental group became better in ego-resilience than the control group who didn't take part in it.Third, After participating in the stress management program, the experimental group became better in job stress coping than the control group who didn't take part in it.The results of this study show that this program is an effective program to reduce social workers' stress by increasing the decentering, ego - resilience and job stress coping of social workers.