The invention discloses a fault-toleration processing method and system for a multi-home terminal in an integrated network. In the method, if no multi-home terminal exists formerly, an access switching router allocates switching-routing identifiers for the multi-home terminal, establishes mapping information and reports the mapping information to home domain mapping servers, and mapping information synchronization is performed among all the home domain mapping servers of the multi-home terminal so as to complete location registration; and if the multi-home terminal exists already, the access switching router modifies the mapping information of the multi-home terminal after discovering a change of an access state of the multi-home terminal and reports the modified mapping information to the home domain mapping server of the located domain of the access switching router, and mapping information update is performed among all the home domain mapping servers of the multi-home terminal and the updated mapping information are announced to the access switching router of a communication opposite end so as to complete location update. According to the method and system disclosed by the invention, the fault-toleration processing function of the multi-home terminal in the internet can be rapidly and completely realized and the reliability and the usability of the network transmission are increased.