The embodiments herein relate to dynamic backup AMF determination and publication. In one embodiment, there proposes a method (900) in a Access and (Start Mobility Management Function (AMF) node (201, 202, 203, 204, 1100), comprising: obtaining (S901) first information of the AMF node (201, 202, 203, 204, 1100), the first information at least includes one or more identifier; obtaining (S902) second information of each of all other nodes (201, 203, 204, 1200) within the same AMF set as the AMF node (201, 202, 203, 204, 1100), the second information includes Relative Capacity (RC) and one or more identifier; and determining (S903) backup AMF for at least one identifier of the AMF (201, 202, 203, 204, 1100) based on the first information and the second information in an autonomous way, without the participation of the Operation Administration and Maintenance (OAM) (206). With embodiments herein, the backup AMF information is determined per GUAMI granularity and published automatically among all AMFs within the AMF set in an autonomous way.