Cardiac arrhythmia is one of the most prevalent cardiovascular diseases worldwide, which can occur alone or be triggered by other diseases, and it can be fatal in severe cases. Recently, Traditional Chinese Medicine has drawn the world’s attention to its effective treatment. As a natural polyhydroxy flavonoid mainly isolated from a variety of plants and foods, quercetin is used for the treatment of cardiovascular disease, cancer, autoimmune diseases, and neurological disorders. A growing number of in vitro experiments and in vivo animal studies have shown that quercetin significantly inhibits mitochondrial oxidative stress, cardiac fibrosis, inflammatory responses, and apoptosis, regulates autophagic responses, improves ischemia/reperfusion injury in cardiomyocytes, and regulates gut microbiota, thereby attenuating or preventing structural and electrical remodeling in the cardiac. Based on these mechanisms, our review provides a systematic overview of the pharmacological actions and molecular targets of quercetin in cardiac arrhythmia caused by multiple etiologies, aiming to provide novel insights and therapeutic strategies to prevent or ameliorate arrhythmia.