A data transmission method, comprising: receiving, by a core network element, data sent from an external network, wherein the data is data sent to a first device group; and sending, by the core network element, the data to an access network element via a first transmission resource, so that the access network element sends the data to a terminal in the first device group via a second transmission resource; wherein the data is transmitted on a control plane among the core network element, the access network element and the terminal; wherein sending, by the core network element, the data to an access network element via a first transmission resource, comprises: if there is a dedicated transmission resource for the first device group between the core network element and the access network element, sending, by the core network element, the data to the access network element via the dedicated transmission resource; if there is no dedicated transmission resource for the first device group between the core network element and the access network element, establishing, by the core network element, the dedicated transmission resource for the first device group between the core network element and the access network element; and sending, by the core network element, the data to the access network element via the dedicated transmission resource; wherein establishing, by the core network element, the dedicated transmission resource for the first device group between the core network element and the access network element, comprises: establishing, by the core network element, the dedicated transmission resource for the first device group between the core network element and the access network element based on group information of the first device group. receiving, by a core network element, data sent from an external network, wherein the data is data sent to a first device group; and sending, by the core network element, the data to an access network element via a first transmission resource, so that the access network element sends the data to a terminal in the first device group via a second transmission resource; wherein the data is transmitted on a control plane among the core network element, the access network element and the terminal; wherein sending, by the core network element, the data to an access network element via a first transmission resource, comprises: if there is a dedicated transmission resource for the first device group between the core network element and the access network element, sending, by the core network element, the data to the access network element via the dedicated transmission resource; if there is no dedicated transmission resource for the first device group between the core network element and the access network element, establishing, by the core network element, the dedicated transmission resource for the first device group between the core network element and the access network element; and sending, by the core network element, the data to the access network element via the dedicated transmission resource; if there is a dedicated transmission resource for the first device group between the core network element and the access network element, sending, by the core network element, the data to the access network element via the dedicated transmission resource; if there is no dedicated transmission resource for the first device group between the core network element and the access network element, establishing, by the core network element, the dedicated transmission resource for the first device group between the core network element and the access network element; and sending, by the core network element, the data to the access network element via the dedicated transmission resource; wherein establishing, by the core network element, the dedicated transmission resource for the first device group between the core network element and the access network element, comprises: establishing, by the core network element, the dedicated transmission resource for the first device group between the core network element and the access network element based on group information of the first device group.