Children are not only the future of the country，but also the hope of families；as the main force of the future social construction，children’s physical and mental health is very important. From the perspective of physiology，psychology and society，medical social workers for children pay attention to humanistic care，effectively give children spiritual，material，psychological and social support，and promote the transformation of clinical practice from disease treatment mode to integrated health service mode. Through the network survey of 129 children’s hospitals in Mainland China，it was found that 26（20.16%）children’s hospitals in 18 provinces claimed to carry out different types and degrees of medical social work services. The study found that the characteristics of medical social work for children practice service are：professional service and voluntary service are in parallel；“medical social worker+” service mode is popular；focus on the “body，mind，sprit and society” all-round service；expand the whole process service in response to the development of Medical Association；the project-based service makes the social work service of each hospital have their own characteristics and show their vitality. These characteristics of social work for children have played a good role in children’s services and care under COVID-19. There are some problems，such as local areas take the lead and regional development is unbalanced；the service of “scratching” is more than that of healing；operational policy lags behind，service is difficult to form a system；professional development lags behind，which affects the professional identity of social workers. Suggestions for the future development of medical social work for children are as follows：The operability of policy must be paid attention to，and the system construction must be strengthened；areas or hospital that has developed ahead of time should give full play to their advantages and carry out counterpart assistance；social workers should integrate various resources to meet the multi-dimensional needs of children with illness and their families；increase publicity efforts to improve the social cognition of children’s medical social work；publicity efforts must be strengthened to improve social cognition.