The present application provides an uplink data transmission method and a user terminal (UE) for executing the method. The method in the present application comprises: A, generating a first random number; B, determining, according to the generated first random number, whether to initiate a random access process; if the random access process is initiated, obtaining a timing advance (TA) value from a base station by means of the random access process; and if the random access process is not initiated, listening for a TA message broadcast by another UE and obtaining a TA value from the TA message; C, transmitting uplink data according to the obtained TA value; D, if the uplink data is successfully transmitted, continuing to perform E, and if the uplink data is unsuccessfully transmitted, returning to A; and E, generating a TA message according to the obtained TA value, and broadcasting the generated TA message. By means of the method in the present application, the time delay and the power consumption can be reduced.