Debit card refers to a bank card issued by the issuing bank to the cardholder, which has no credit limit and the cardholder deposits first and then uses it. It is one of the types of bank cards. Debit cards are divided into transfer cards, special cards and stored value cards according to different functions. Their advantages are easy to use, popular, safe and reliable. It can't be overdrawn, and has the functions of transfer, cash deposit and withdrawal and consumption. There are two ways to use it: password and signature. Debit cards are becoming more and more popular, which can easily replace cash and checks for consumption and transactions. In recent years, debit cards have gradually become the most popular payment cards. Hundreds of millions of debit cards are being used all over the world. Debit cards mostly have the functions of saving in local and foreign currencies, fixed term and current account, etc. Debit cards can deposit and withdraw money at card-issuing bank outlets and self-service banks, and can also withdraw money at ATMs (cash machines) in China and even around the world.