The present invention discloses a bank transaction method linking accounts via common accounts, wherein the existing accounts of the account holder and/or newly opened plural accounts link arbitrarily as defined by the account holder for convenient transactions between account holder's primary account and other's secondary accounts without using account numbers of the concerned accounts. To fulfill, the purpose, the present invention enables the account holder to make transactions on a primary account as well on linked secondary accounts in real time; and the said primary and secondary accounts are also offered for independent transaction as ordinary bank accounts. In addition, the classification and management of the said primary and secondary accounts are attainable through the individual account number with specified account code given by the bank to achieve transactions between the said primary and secondary accounts while implementing the conventional banking system. Furthermore, transaction to the external transaction network including payment gateway can be processed without changing the existing data format, both of account holders' and bank's convenience is maximized.