Abstract: The autonomic nervous system exerts an important role in cardiovascular diseases.Recent studies have shown that decreased vagal tone is closely related to high morbidity and poor prognosis.Increase in vagal tone ameliorates myocardial damage and protects myocardial function.Improving vagal tone provides a new set of strategies and promising approaches for therapy of cardiovascular diseases.This article reviews the evaluation indicators and improved methods of vagal tone to provide a theoretical basis and direction for further research of vagal regulation.