Abstract: The present invention discloses a method for remote payment based on a mobile terminal. The method includes: an authentication server asking a mobile terminal for a digital certificate, the mobile terminal transmitting an certificate reading instruction to the built-in smart card, and after the smart card exports the stored digital certificate, the mobile terminal transmitting it to the authentication server for certificate registration, and the authentication server sending a signature instruction to the mobile terminal, the mobile terminal transmitting a private key signature instruction to the built-in smart card, the smart card sending out the signature result and the mobile terminal reporting the signature result to the authentication server. The present invention also discloses a system for remote payment based on mobile terminal, a mobile terminal and a smart card.