It has been a long period since social workers first provided various immediate services for patients in need of urgent medical treatments in emergency rooms. However, as the society evolves, the role of ER social workers has shifted from helping with unidentified patients, medical subsidies and discharge arrangement to handling miscellaneous cases such as senior citizens living alone, family violence, sexually abused victims, children and senior citizens abuse, suicide, drug and alcohol addiction, mental illness, homelessness, Dead on Arrival (DOA) and severe accidents; Moreover, ordinary ER visits are also included in the scope of ER social workers' services. When unaccompanied and unidentified patients seek medical treatments in ER, hospital staff will contact social workers in no time to find their family members for the follow-up medical procedure. However, ER social workers have bumped into more difficulties to locate patient's family members due to family alienation developed by the change of family mode in recent years and the Personal Information Protection Act enforced on October 1st, 20. In light of this, this study aims to understand the service provided by ER social workers in National Taiwan University Hospital (NTUH) in the case of unaccompanied patients, to analyze the intervention made by the Social Work Office in NTUH and the obstacles and challenges faced in these processes. Unlike the perspective of previous research which focused on service receivers, this study emphasizes on the intervention made by social workers and social work organization as a whole in the hope of providing specific suggestions to make contribution to hospital practice.