To understand the compliance, influencing factors, and action path of family cardiac rehabilitation exercise prescriptions for children after congenital heart disease surgery. A random sampling method was used to select 200 paediatric patients and their parents from a paediatric hospital in Shanghai. Among them, 57 cases (28.5%) of children's families followed the cardiac rehabilitation exercise prescription. Path analysis showed that peak oxygen uptake exerted a negative impact on the compliance of family cardiac-rehabilitation prescriptions for patients after congenital heart disease surgery through doctor-patient trust, with a standardized path coefficient of -0.246 (P = 0.001). Disease-related knowledge exerted a positive effect on the compliance of family cardiac-rehabilitation prescriptions for children after congenital heart surgery through doctor-patient trust, with a standardized path coefficient of 0.353 (P < 0.001). The dimension of friend support in social support had a direct positive effect on the compliance of family cardiac-rehabilitation prescriptions for children after cardiac surgery, with a standardized path coefficient of 0.641 (P = 0.006). The compliance of cardiac rehabilitation exercise prescription in children with congenital heart disease is not good and is affected by many factors, and there is a complex path relationship between various factors; the kilogram oxygen consumption of the child, the disease-related knowledge of the caregiver, and social support all play important roles in the compliance of the child's family's health prescription. ChiCTR2200062022.