A method and a device are provided in a UE and a base station for wireless communication. The UE receives a first signaling, and operates a first radio signal in K time domain resource(s). The first signaling is used for determining the K time domain resource(s), K is a positive integer; the first radio signal carries a first bit block, a first time-domain-resource size and a target parameter are used for determining the size of the first bit block, at least one of the K time domain resource(s) is used for determining the first time-domain-resource size; the target parameter is a first or a second parameter; whether the target parameter is the first parameter or the second parameter is related to the first time-domain-resource size, or, whether the target parameter is the first parameter or the second parameter is related to the K; the operating action is transmitting or receiving.