The present disclosure discloses a system and a method for automatic call synchronization. When a mobile terminal receives a called signal from a calling mobile terminal and determines that an automatic call synchronization function is enabled by itself, the mobile terminal transmits, to a wireless signal transponder, a call synchronization request which carries identification information and call information of the mobile terminal; a mode recognition unit which is connected to the wireless signal transponder performs an authentication on the mobile terminal according to the identification information of the mobile terminal; and transmits a call access request which carries the identification information and the call information of the mobile terminal to the fixed terminal via the wireless signal transponder, after the authentication on the mobile terminal is passed; the fixed terminal calls a user of the mobile terminal according to the identification information and the call information; and transmits a call access response to the wireless signal transponder when it is determined that the user of the mobile terminal answers the call with the fixed terminal, and completes communication for the call over a network connected between the calling mobile terminal and the fixed terminal. As such, phone charge may be saved, and call synchronization may be performed automatically, which have flexibility and convenience, and bring convenience to the user.