The invention discloses a bank card transaction system and a method based on real-time interaction of a short-message platform. The system comprises a mobile communication terminal, a transaction terminal, a short message service center and a bank account management center and further comprises a main bank card, a secondary bank card, a bank account management center front-end processor, a short message service center front-end processor and a related information database. The method comprises the steps: performing transactions under a primary account in the way of card swiping by account grading and discrimination processing of various different transaction terminals such as a POS (point-of-sale) machine, an ATM (automatic teller machine), a bank counter machine and an online PC (personal computer) and the like; performing transactions under a secondary account in the way of card swiping and password inputting; and performing transactions under a trilevel account in the way of card swiping, password inputting and short message authentication. By the system and method disclosed by the invention, the great convenience of daily small-amount payment of the bank cards and the reliability and safety of large-amount and online transaction are achieved.