The present disclosure provides an uplink signal transmission method, user equipment (UE) and base station. When the UE transmits uplink signals in an unlicensed frequency band after receiving uplink synchronization command information, the UE transmits one or more uplink signals according to a predefined time or a time indicated by the base station. The UE determines mapping of an uplink signal according to the predefined time or the indicated time. When provided with the present disclosure, interference between signals of a same type or between signals of different types can be reduced and a signal transmission probability can be improved accordingly.