A method, an apparatus, a terminal, and a base station for data transmission are provided. The method includes: when downlink data is received after a TAT expires, determining whether a first preset parameter of a UE satisfies a first uplink synchronization maintenance condition; and when the first parameter of the UE satisfies the first uplink synchronization maintenance condition, sending, to a base station, a feedback corresponding to the downlink data; or when the first parameter of the UE does not satisfy the first uplink synchronization maintenance condition, skipping sending, to the base station, a feedback corresponding to the downlink data, where the feedback is used to indicate whether the downlink data is received correctly, and the first synchronization maintenance condition is used to determine that the UE still maintains an uplink in-sync state after the TAT expires.