In June 2016, China promulgated the “Opinions of the State Council on Strengthening the Work of Rescuing Children in Difficulty”, which broadened the coverage of child welfare in China. The document clearly encourages and supports the participation of nonprofit charitable organizations in improving and complementing the public support system for children living in difficulty. This paper reports an assessment study of the relief program for children with congenital heart disease, which was launched by the Red Cross in L Province. Semi-structured face-to-face interviews with six Red Cross employees and 10 parents of stricken families, and telephone interviews with 66 recipient families, were carried out. Additionally, a review of a large number of background documents was analyzed to assess interventions by social organizations in the rescue of children in difficulty. The project was shown to reduce poverty and improve medical treatment for children with congenital heart disease. The role of nonprofit charitable organizations in relation to the child protection system can be characterized as “leak-filling”.