A data transmission method, comprising: judging whether to adopt a data transmission mode of a direct connection communication according to a service request received by a network side or triggered by the network side; determining a data source node and a data reception target node corresponding to the service request when a judgment result is to adopt the data transmission mode of the direct connection communication; characterized by selecting a bearer network node corresponding to the data source node and the data reception target node according to a physical domain network selection principle and a business mode domain network selection principle; and determining a network structure corresponding to the data transmission mode of the direct connection communication according to the bearer network node, the data source node and the data reception target node, wherein the bearer network node is a node of a bearer network for bearing direction connection communication, wherein the physical domain network selection principle is a principle of selecting a transfer UE for a lower-layer physical domain network in the direct connection communication network, and the business mode domain principle is a principle of selecting a data transfer UE for the bearer network in the direct connection communication network, wherein the determining the data source node and the data reception target node corresponding to the data transmission request specifically comprises: determining the data source node corresponding to the service request and searching a target node interested in a service corresponding to the service request and/or a target node in a plurality of service domains in a same interest group with the data source node; and regarding the service domain target node as the data reception target node. judging whether to adopt a data transmission mode of a direct connection communication according to a service request received by a network side or triggered by the network side; determining a data source node and a data reception target node corresponding to the service request when a judgment result is to adopt the data transmission mode of the direct connection communication; characterized by selecting a bearer network node corresponding to the data source node and the data reception target node according to a physical domain network selection principle and a business mode domain network selection principle; and determining a network structure corresponding to the data transmission mode of the direct connection communication according to the bearer network node, the data source node and the data reception target node, wherein the bearer network node is a node of a bearer network for bearing direction connection communication, wherein the physical domain network selection principle is a principle of selecting a transfer UE for a lower-layer physical domain network in the direct connection communication network, and the business mode domain principle is a principle of selecting a data transfer UE for the bearer network in the direct connection communication network, wherein the determining the data source node and the data reception target node corresponding to the data transmission request specifically comprises: determining the data source node corresponding to the service request and searching a target node interested in a service corresponding to the service request and/or a target node in a plurality of service domains in a same interest group with the data source node; and regarding the service domain target node as the data reception target node.