An access method performed by a system comprising a mobility management device, a user equipment, UE, a portal server and a gateway device, the method comprising: • receiving, by the mobility management device, an access request message sent by the UE, wherein the access request message comprises first indication information, and the first indication information is used for indicating that the UE performs equipment access, wherein the equipment access is a procedure in which the UE registers in a mobile communications network when there is no valid subscription data of the UE (step 201); and • performing, by the mobility management device, the equipment access for the UE according to the first indication information, wherein the access request message is an attach request message, by: ∘ constructing, by the mobility management device, a context of the UE, wherein the context of the UE is generated according to the first indication information by the mobility management device according to local configuration data or default data (step 203); before accepting by the mobility management device the access request message according to the first indication information, performing the following steps: ∘ sending, by the mobility management device, a create session request message to the gateway device according to the first indication information, wherein the create session request message comprises second indication information, and the second indication information is used for instructing the gateway device to perform a charging policy for a data service of the UE (step 204); wherein according to the charging policy the gateway device sends a triggering message to the portal server to trigger to complete charging processing; and thereafter ∘ accepting, by the mobility management device, the access request message according to the first indication information (step 206); • sending, by the gateway device, the triggering message to the portal server (step 208); • sending, by the portal server, a webpage for data service charging to the UE according to the received triggering message, wherein the webpage prompts a user of the UE to input a credit card account number to purchase a charging quota or to input information of an existing charging account. • receiving, by the mobility management device, an access request message sent by the UE, wherein the access request message comprises first indication information, and the first indication information is used for indicating that the UE performs equipment access, wherein the equipment access is a procedure in which the UE registers in a mobile communications network when there is no valid subscription data of the UE (step 201); and • performing, by the mobility management device, the equipment access for the UE according to the first indication information, wherein the access request message is an attach request message, by: ∘ constructing, by the mobility management device, a context of the UE, wherein the context of the UE is generated according to the first indication information by the mobility management device according to local configuration data or default data (step 203); before accepting by the mobility management device the access request message according to the first indication information, performing the following steps: ∘ sending, by the mobility management device, a create session request message to the gateway device according to the first indication information, wherein the create session request message comprises second indication information, and the second indication information is used for instructing the gateway device to perform a charging policy for a data service of the UE (step 204); wherein according to the charging policy the gateway device sends a triggering message to the portal server to trigger to complete charging processing; and thereafter ∘ accepting, by the mobility management device, the access request message according to the first indication information (step 206); ∘ sending, by the mobility management device, a create session request message to the gateway device according to the first indication information, wherein the create session request message comprises second indication information, and the second indication information is used for instructing the gateway device to perform a charging policy for a data service of the UE (step 204); wherein according to the charging policy the gateway device sends a triggering message to the portal server to trigger to complete charging processing; and thereafter ∘ accepting, by the mobility management device, the access request message according to the first indication information (step 206); • sending, by the gateway device, the triggering message to the portal server (step 208); • sending, by the portal server, a webpage for data service charging to the UE according to the received triggering message, wherein the webpage prompts a user of the UE to input a credit card account number to purchase a charging quota or to input information of an existing charging account.