The present disclosure provides a method and a device in a node for wireless communications. A first node receives a first signaling and a first signal in a first time-frequency resource pool; the first signaling comprises scheduling information of the first signal; the first signal carries a first bit block, the first bit block comprising a positive integer number of binary bits; a first value is used for determining a number of binary bits comprised in the first bit block, and the first value is related to the first time-frequency resource pool. The above method helps prevent both sides of communications from different interpretations of Transport Block Size in V2X communications, thus ensuring communication quality and avoiding extra signaling overhead.