The disclosure provides a method and a device in a User Equipment (UE) and base station for unlicensed spectrum. The UE first monitors a first signaling, and then, if the first signaling is detected, monitors a second signaling, or receives a first radio signal, wherein the first signaling includes a first field; the first signaling carries first sub-information besides the first field, or the first signaling carries second sub-information besides the first field; the first field in the first signaling is used for determining whether the first sub-information or the second sub-information is carried in the first signaling; the first sub-information is used for determining a first time-frequency resource pool, time-frequency resources occupied by the second signaling belong to the first time-frequency resource pool, and the second sub-information is used for determining time-frequency resources occupied by the first radio signal. The disclosure can improve the utilization of unlicensed spectrum resources.