The invention relates to a method and a system for processing roaming service. The method comprises the following steps that a home location service platform receives and stores a roaming service list distributed by a roaming location service platform through a national service platform; a user terminal subscribes roaming service according to the roaming service list stored by the home location service platform, and transmits user information including subscription information to the roaming location service platform; the home location service platform receives a first receipt message from the roaming location service platform, and stores the subscription information in HLR; the user terminal automatically registers in roaming location VLR, the roaming VLR/MSC acquires the information subscribed by the user including the roaming service, and informs a message that the user arrives at the roaming location to the roaming location service platform; the roaming location service platform provides service for the user terminal according to the roaming service subscribed by the user. The method and the system for processing the roaming service realize timely, correct, quick and convenient roaming location service for the user, and improve satisfaction degree and experience degree of the user.