Congenital ductus arteriosus and atrial and ventricular septal defects are several common uncomplicated congenital heart malformations. With the development and maturation of percutaneous interventional techniques and improvement of implant materials in recent years, more and more patients are treated with percutaneous catheter interventional occlusion for these uncomplicated congenital heart diseases. Compared with traditional open-heart surgery, this treatment technique has the advantages of less injury, less pain, no chest opening, no need for tracheal intubation and extracorporeal circulation, and faster postoperative recovery, especially for patients with reversible pulmonary hypertension and possible postoperative respiratory care difficulties, which avoids increased lung damage due to surgical procedures and extracorporeal circulation diversion, thus reducing the length of hospitalization and alleviating the pain and burden of patients. However, it should not be overlooked that detachment of the blocker is one of the serious complications of this technique. A dislodged blocker can embolize vital organs with serious consequences. Most of the dislodged blockers are related to the technique. Dislodgement of atrial septal defect (ASD) blockers is the most common, followed by ventricular septal defect (VSD) blockers, while dislodgement of patent ductus arteriosus (PDA) blockers is relatively uncommon. The main causes of blocker dislodgement are (1) overly broad indications: for example, in ASD blocking, blocker dislodgement occurs mostly in cases with inadequate or thin inferior vena cava margins. In VSD occlusion, if the diameter of VSD is large and the pulmonary artery pressure is high, the risk of blocker dislodgement increases accordingly, therefore, preoperative hemodynamic indexes and surgical risks need to be evaluated comprehensively. (2) Small blocker selection: Underestimation of defect diameter and small blocker selection are also common causes of blocker dislodgement. Of course, the choice of blocker should not be large, otherwise it will easily cause poor morphology and atrioventricular conduction block after blocking. Selecting the appropriate blocker according to different anatomical conditions is an important guarantee to prevent blocker dislodgement. (3) Dislodgement caused by improper operation: The dislodgement of blocker usually occurs intraoperatively, but a small part of it occurs postoperatively, usually due to poor position when releasing, and then dislodged by body position and heartbeat. The dislodgement of the blocker is extremely rare in postoperative discharge, which is mainly due to the fact that the dislodgement does not cause symptoms and is detected late. The symptoms and risks of blocker dislodgement are mainly related to the site of dislodgement; ASD blocker can be dislodged into the left atrium, left ventricle, right atrium, right ventricle and pulmonary artery; dislodgement into the atrium can cause premature atrial beats, chest pain, chest tightness and other symptoms; dislodgement into the ventricle can cause palpitations, premature ventricle, ventricular tachycardia and other ventricular arrhythmias. Prolapse into the pulmonary artery may cause changes similar to pulmonary embolism. It can be detected by emergency fluoroscopy and echocardiography. The VSD blocker can be dislodged into the left ventricle, right ventricle, pulmonary artery, and body circulation, etc. The right ventricle and pulmonary artery are the most common ones. The right ventricle and pulmonary artery are the most common. The PDA blocker is usually dislodged into the abdominal aorta and iliac artery, which may cause abdominal pain. There are also cases of dislodgement into the pulmonary artery, but due to its large size, it rarely dislodges into the intracranial arterial system. For dislodgement of the blocker, emergency surgical treatment is usually required. Patients with such serious complications should be treated surgically as soon as possible. Intraoperative ultrasound and fluoroscopic monitoring, postoperative electrocardiographic monitoring, and 24h postoperative follow-up ultrasound, chest radiograph, and electrocardiogram are important to ensure timely detection, and once it is clear that the blocker is dislodged, interventional removal can be attempted first, but if interventional removal is difficult and time-consuming, surgery should be decisively performed to avoid delaying the disease and causing serious adverse consequences or even death. In conclusion, a skilled surgical team must escort the heart center where the interventional procedure is performed, otherwise the dislodgement of the blocker will become a catastrophic event.