Abstract: In recent years, the rapid development of molecular biology and molecular electrophysiology has opened up a new era of arrhythmia mechanism research. Arrhythmias are clearly associated with abnormal expression of ion channel genes, and genes mutations in multiple ion channel can cause various arrhythmias. At present, most of the primary electrocardiographic abnormalities are caused by gene mutations encoding the major ion channel subunits. Therefore, such diseases can be referred to as ion channel diseases. The Nav1.5 channel is the main type of cardiac sodium channel in humans and is responsible for the initiation and propagation of action potentials. It is encoded by SCN5A gene. Since the first mutation in the gene SCN5A of the cardiac sodium channel alpha subunit was found in the family of long QT syndrome. Hundreds of mutations have been found to be associated with a range of hereditary arrhythmias. Such as, long QT syndrome type 3 (LQT3), Brugada syndrome, progressive cardiac conduction block (PCCD), dilated cardiomyopathy (DCM), sudden infant death syndrome (SIDS), etc. In recent years, it has been found that SCN5A gene mutation is closely related to sick sinus syndrome, atrial arrhythmia (atrial fibrillation, atrial standstill), ventricular arrhythmia and poor pacemaker capture. This article will elaborate on the recent SCN5A gene mutation in sick sinus syndrome (SSS), atrial arrhythmia (atrial fibrillation, atrial standstill), poor pacemaker capture, ventricular arrhythmia and long QT syndrome type 3, the potential mechanisms of gain-of- function and loss-of-function SCN5A mutations, and current problems and challenges.