Embodiments of the present invention disclose a data transmission method and apparatus for a terminal. The terminal exchanges data of an application with a server through a first port by using a first access node; when one port in a second port set is in an enabled state, accesses one access node in a candidate access node set through the enabled port in the second port set, and exchanges, based on the Multipath TCP transmission protocol, the data of the application with the server by using an access node corresponding to the enabled port. Therefore, during data transmission link aggregation or switching, network resources are fully utilized and data transmission efficiency is improved.