Abstract: The present invention provides a system and method for reducing loads of a mobility management entity in core networks. An object sending a connection-request message asking for network access to a base station through a wireless network; the base station receiving the connection-request message and sending it to core networks through a network; a mobility management entity (MME) in the core network receive the connection-request message. If the core network is busy and refuses to interconnect with the object, MME calculating according to a management rule a back-off time; MME transmitting a response message including the back-off time to the object through the base station, and the object sending out a connection-request message again after the back-off time has elapsed according to the response message.