A network node, comprising: a processing unit, configured to determine a link adjustment policy, wherein the link adjustment policy is usable to determine, from a Multipath Transmission Control Protocol, MPTCP, sublink that corresponds to the network node and belongs to an MPTCP connection, a first MPTCP sublink on which link control needs to be performed, and determine an adjustment manner applicable to the first MPTCP sublink; wherein the MPTCP connection includes one MPTCP primary link and at least one MPTCP sublink; and a sending unit, configured to send the link adjustment policy to a link control node; wherein the network node is located on a transmission path of the MPTCP sublink and is configured to support data communication between two communication parties that use the MPTCP connection; characterised in that the link adjustment policy comprises: when the radio resource status of the network node and/or the link quality status of the MPTCP sublink indicates that a load of the network node exceeds a first preset threshold, the adjustment manner is stopping the first MPTCP sublink from completing a TCP subflow joining process; or when the link quality status of the MPTCP sublink indicates that link performance of the first MPTCP sublink is lower than a second preset threshold, and a current status of the first MPTCP sublink indicates that the first MPTCP sublink is available, the adjustment manner is deleting the first MPTCP sublink; or when the link quality status of the MPTCP sublink indicates that link performance of the first MPTCP sublink is higher than a third preset threshold, and a current status of the first MPTCP sublink indicates that the first MPTCP sublink is a secondary link, the adjustment manner is increasing the priority of the first MPTCP sublink. a processing unit, configured to determine a link adjustment policy, wherein the link adjustment policy is usable to determine, from a Multipath Transmission Control Protocol, MPTCP, sublink that corresponds to the network node and belongs to an MPTCP connection, a first MPTCP sublink on which link control needs to be performed, and determine an adjustment manner applicable to the first MPTCP sublink; wherein the MPTCP connection includes one MPTCP primary link and at least one MPTCP sublink; and a sending unit, configured to send the link adjustment policy to a link control node; wherein the network node is located on a transmission path of the MPTCP sublink and is configured to support data communication between two communication parties that use the MPTCP connection; characterised in that the link adjustment policy comprises: when the radio resource status of the network node and/or the link quality status of the MPTCP sublink indicates that a load of the network node exceeds a first preset threshold, the adjustment manner is stopping the first MPTCP sublink from completing a TCP subflow joining process; or when the link quality status of the MPTCP sublink indicates that link performance of the first MPTCP sublink is lower than a second preset threshold, and a current status of the first MPTCP sublink indicates that the first MPTCP sublink is available, the adjustment manner is deleting the first MPTCP sublink; or when the link quality status of the MPTCP sublink indicates that link performance of the first MPTCP sublink is higher than a third preset threshold, and a current status of the first MPTCP sublink indicates that the first MPTCP sublink is a secondary link, the adjustment manner is increasing the priority of the first MPTCP sublink. when the radio resource status of the network node and/or the link quality status of the MPTCP sublink indicates that a load of the network node exceeds a first preset threshold, the adjustment manner is stopping the first MPTCP sublink from completing a TCP subflow joining process; or when the link quality status of the MPTCP sublink indicates that link performance of the first MPTCP sublink is lower than a second preset threshold, and a current status of the first MPTCP sublink indicates that the first MPTCP sublink is available, the adjustment manner is deleting the first MPTCP sublink; or when the link quality status of the MPTCP sublink indicates that link performance of the first MPTCP sublink is higher than a third preset threshold, and a current status of the first MPTCP sublink indicates that the first MPTCP sublink is a secondary link, the adjustment manner is increasing the priority of the first MPTCP sublink.