Sudden cardiac death (SCD) refers to death within 1 hour after onset of cardiovascular disease or death within 24 hours from the last stable status. SCD has a high incidence and mortality rate. The relationship between heart autonomic nerves, especially sympathetic nerve and SCD, is the focus of study. The increase and/or heterogeneity of sympathetic activity and the remodeling of sympathetic innervation can lead to arrhythmogenic substrate in the heart or even SCD. Medicine treatment, implanted cardioverter defibrillator, left cardiac sympathetic denervation, renal sympathtic nerves ablation and spine stimulation have obtained encouraging outcomes. Therefore the present paper reviews the autonomic system, especially sympathetic nerves, and its relationship with cardiac arrhythmia.