Neonatal atrial septal defect of 3mm can heal spontaneously, and the self-healing time is usually within one and a half years of age. Children with an atrial septal defect of 3mm or less only need regular ultrasound review, while children with an atrial septal defect of 3mm or more need to develop an individualized treatment plan based on the ultrasound review and choose the right time for surgery to improve their heart function. Usually, two types of surgical treatment can be chosen: interventional treatment and open-heart surgical treatment. For older children, interventional treatment can be performed if the defect location is suitable, which is less invasive and has more definite results. For those who are not suitable for intervention, or those with recurrent pneumonia and recurrent heart failure, surgical treatment is needed. Small axillary incision direct vision surgery can be chosen for infants or children, which is also less traumatic.