A network connection re-establishment method for a mobility management entity, MME, comprising: receiving a bearer update request message forwarded by a serving gateway, wherein the bearer update request message comprises an Internet Protocol, IP, address allocated to a user equipment, UE, and the bearer update request message is sent to the serving gateway when a data gateway allocates the IP address of the UE by using the Dynamic Host Configuration Protocol; storing the IP address of the UE into a base of user information; receiving a network connection re-establishment trigger message sent by the data gateway, wherein sending of the network connection re-establishment trigger message is triggered when the data gateway detects that gateway resetting occurs and receives a downlink packet delivered by a packet data network; determining that a type of the gateway resetting is resetting of a data gateway or resetting of a serving gateway; and re-establishing, according to the type of the gateway resetting, a network connection corresponding to the downlink packet; wherein the type of the gateway resetting is resetting of a data gateway, the network connection re-establishment trigger message comprises a UE IP address extracted from the downlink packet; and wherein re-establishing the network connection corresponding to the downlink packet comprises that: querying locally the stored base of user information according to the UE IP address comprised in the network connection re-establishment trigger message, finding PDN connection information corresponding to the UE, and initiating a PDN connection deactivation procedure to PDN connections that need to be recovered. receiving a bearer update request message forwarded by a serving gateway, wherein the bearer update request message comprises an Internet Protocol, IP, address allocated to a user equipment, UE, and the bearer update request message is sent to the serving gateway when a data gateway allocates the IP address of the UE by using the Dynamic Host Configuration Protocol; storing the IP address of the UE into a base of user information; receiving a network connection re-establishment trigger message sent by the data gateway, wherein sending of the network connection re-establishment trigger message is triggered when the data gateway detects that gateway resetting occurs and receives a downlink packet delivered by a packet data network; determining that a type of the gateway resetting is resetting of a data gateway or resetting of a serving gateway; and re-establishing, according to the type of the gateway resetting, a network connection corresponding to the downlink packet; wherein the type of the gateway resetting is resetting of a data gateway, the network connection re-establishment trigger message comprises a UE IP address extracted from the downlink packet; and wherein re-establishing the network connection corresponding to the downlink packet comprises that: querying locally the stored base of user information according to the UE IP address comprised in the network connection re-establishment trigger message, finding PDN connection information corresponding to the UE, and initiating a PDN connection deactivation procedure to PDN connections that need to be recovered.