Provided in the present invention are a data transmission method and device. In an embodiment of the present invention, in a condition in which a first node acquires whether an X2 interface is present between the first node and a second node, the first node directly transmits a forwarding address thereof to the second node, to address a problem in the related art regarding how to optimize data forwarding in a scenario of double connection switching, thereby improving flexibility and applicability of the data forwarding.