Leadless pacemaker emerged as a new pacing strategy to avoid pocket and lead-related complications as compared with conventional pacemaker. Whereas, cardiac perforation remains a major safety concern during the implantation. Herein, we presented a rare case of cardiac perforation with pericardial tamponade caused by accidently placing the delivery catheter into the coronary sinus and she was successfully recovered after immediate pericardiocentesis and discharged without other adverse events.