User data backup and acquisition methods, systems and devices

The invention discloses a user data backup method, a user data backup system and a user data backup device, which are used for solving the problem that storage resources of user data in a mobile switching controller (MSC) pool are relatively fewer. The user data backup method comprises that: a first mobile switching controller acquires the user data provided by a home location register (HLR); and the user data is backed up to a second mobile switching controller in the same mobile switching controller pool where the first mobile switching controller is. The invention also discloses a user data acquisition method, a user data acquisition system and a user data acquisition device, which are used for solving the problem of HLR processing resource shortage caused in the switching of a plurality of users between the MSCs/visited location registers (VLR). The user data acquisition method comprises that: the first mobile switching controller determines the second mobile switching controller in which the user data is backed up in the mobile switching controller pool where the first mobile switching controller is, wherein the user data is the user data of the user currently switched to the first mobile switching controller; and the first mobile switching controller acquires the user data from the determined second mobile switching controller.