A Device Management (DM) method, a DM apparatus and a DM system are provided. The DM method includes: receiving a DM instruction; parsing the DM instruction to be used for managing at least two terminal devices, in which management data, used for managing the at least two terminal devices, indicated in the DM instruction is the same; obtaining the management data indicated in the DM instruction only once; and delivering the obtained management data to the at least two terminal devices so that the at least two terminal devices perform DM according to the management data. The utilization of an external interface of a gateway device may be improved by adopting the DM method, the DM apparatus and the DM system.