A UE and a data transmission method thereof are provided. The method includes: acquiring configuration information of a first shortened TTI sent by a base station; blindly detecting a predetermined physical downlink link control channel with a period of the first shortened TTI, until primary DCI corresponding to the UE is acquired; determining secondary DCI corresponding to the UE based on the acquired primary DCI; and performing data transmission with the base station in a second shortened TTI scheduled by the secondary DCI. Flexibility of application of a shortened TTI may be improved, and resources may be saved.