The invention provides a temporary mobile station identity TMSI allocation method, comprising steps of: notifying a mobility management entity MME device of a corresponding mobility attribute based on a type of a Machine Type Communication MTC application, wherein the mobility attribute indicates whether a mobility of the MTC application is high or low; determining, by the MME device, a mobility layer associated with the MTC application according to the mobility attribute, and then allocating a TMSI from an available address space to a MTC device applying the MTC application based on a predetermined criterion, according to the determined mobility layer. The present invention further provides corresponding MTC server, MME device, network attachment method and location area update method.