Leukemia is the most common types of cancer for children. There are about 4 million patients with leukemia in China，and half of them are children. Children with leukemia can’t go to school due to long-term hospitalization. This paper aims to explore how to provide social work service for long-term hospitalized children in hospital. Through participant observation，questionnaire and depth interview，we took medical social work practice in Tongji Hospital，Tongji University School of Medicine. We developed a series of social work service for long-term hospitalized children such as visiting ward every day，talking with parents，assessing requirements，taking group work in ward，building activity space for children. Finally，combined with the actual discussion and give advices on the？development，discuss the theory of meaning perspective，professional education of social work and supervision for practice.