In view of the security and practicability requirements of an electronic payment system as well as the problems of complicated steps and trivial signature processes and others in the traditional electronic payment protocol based on controlled teleportation, we propose an electronic payment protocol based on quantum dense coding. The proposed protocol uses quantum operations such as quantum key distribution, single particle measurement, Bell measurement, and unitary operator to perform message blinding, authorization, signature and verification processes in order, and thus completes the whole electronic payment process. In the new protocol, the three-particle entangled state is used as the quantum channel, which can use less resources to complete transactions among different banks. Moreover, by using dense coding instead of controlled teleportation, it is possible to transmit two-bit classical messages with only one qubit. The security analysis shows that the protocol can guarantee the blindness of the purchase information, and satisfy the undeniability, unforgeability and unconditional security.