This application relates to a communication method and device. The communication method includes: receiving first signaling, where the first signaling indicates to deactivate that a first logical channel; and determining, depending on whether a logical channel in an activated state and the first logical channel belong to a same MAC entity, whether an association relationship between a carrier and the logical channel in the activated state applies, where the first logical channel and the logical channel in the activated state belong to a same radio bearer, and a PDCP duplication transmission function is configured for the radio bearer. According to the method provided in embodiments of this application, after a logical channel is deactivated, carriers that should be used for a remaining logical channel can be known, so that a terminal device can perform a correct operation.