A data transmission control node, configured to control data transmission between two communication parties of a Multipath Transmission Control Protocol, MPTCP, connection, wherein the MPTCP connection comprises multiple Transmission Control Protocol, TCP, subflows, and the data transmission control node is configured to be independently deployed, and is further configured to have a link connection with at least one access network side node, so as to facilitate information exchange with the at least one access network side node and comprises: a processing unit, configured to select at least one TCP subflow on which data transmission control needs to be performed from the multiple TCP subflows; wherein the processing unit is further configured to determine an adjustment policy for an input item of an MPTCP congestion control algorithm; a sending unit, configured to send the adjustment policy to an access network side node corresponding to the at least one TCP subflow; and an information management unit, configured to associate the multiple TCP subflows with the MPTCP connection according to an MPTCP connection message, to make the MPTCP connection comprise the multiple TCP subflows, wherein the MPTCP connection message is used to indicate a status of the MPTCP connection, wherein the adjustment policy is used to instruct the access network side node to adjust a data transmission process on the at least one TCP subflow and trigger the two communication parties to perform the MPTCP congestion control algorithm, and an output result of the MPTCP congestion control algorithm comprises determining to migrate a part or all of data transmitted on the at least one TCP subflow to another TCP subflow that belongs to the MPTCP connection, wherein the access network side node is configured to be located in a communication link between the two communication parties, wherein that the processing unit is configured to determine an adjustment policy for an input item of an MPTCP congestion control algorithm comprises: determining to reduce a data transmission rate of the at least one TCP subflow, and determining a reduction degree of the data transmission rate, wherein that the adjustment policy is used to instruct the access network side node to adjust a data transmission process on the at least one TCP subflow comprises: the adjustment policy is used to instruct the access network side node to discard a service data packet on the at least one TCP subflow to increase the packet loss rate, wherein a quantity of discarded service data packets is corresponding to the reduction degree of the data transmission rate. a processing unit, configured to select at least one TCP subflow on which data transmission control needs to be performed from the multiple TCP subflows; wherein the processing unit is further configured to determine an adjustment policy for an input item of an MPTCP congestion control algorithm; a sending unit, configured to send the adjustment policy to an access network side node corresponding to the at least one TCP subflow; and an information management unit, configured to associate the multiple TCP subflows with the MPTCP connection according to an MPTCP connection message, to make the MPTCP connection comprise the multiple TCP subflows, wherein the MPTCP connection message is used to indicate a status of the MPTCP connection, wherein the adjustment policy is used to instruct the access network side node to adjust a data transmission process on the at least one TCP subflow and trigger the two communication parties to perform the MPTCP congestion control algorithm, and an output result of the MPTCP congestion control algorithm comprises determining to migrate a part or all of data transmitted on the at least one TCP subflow to another TCP subflow that belongs to the MPTCP connection, wherein the access network side node is configured to be located in a communication link between the two communication parties, wherein that the processing unit is configured to determine an adjustment policy for an input item of an MPTCP congestion control algorithm comprises: determining to reduce a data transmission rate of the at least one TCP subflow, and determining a reduction degree of the data transmission rate, wherein that the adjustment policy is used to instruct the access network side node to adjust a data transmission process on the at least one TCP subflow comprises: the adjustment policy is used to instruct the access network side node to discard a service data packet on the at least one TCP subflow to increase the packet loss rate, wherein a quantity of discarded service data packets is corresponding to the reduction degree of the data transmission rate.