Embodiments of the present invention provide a data transmission method. The method includes: obtaining a slot format of a F-DPCH used for a UE; receiving an ACK message that is sent by a base station on an AICH; determining an F-DPCH frame offset τF-DPCH of the UE and determining a transmission time interval τa-m according to a predefined rule, where the τa-m indicates a time interval between a starting boundary of an access slot when the UE receives the AICH and a time point when the UE starts uplink transmission; receiving an uplink power control command word TPC on the F-DPCH according to the slot format of the F-DPCH and the τF-DPCH; and performing uplink transmission to the base station according to the τa-m.