A command indication method and apparatus and information interaction method and apparatus. The command indication method includes: transmitting to a user equipment (UE), a command for activating or deactivating duplication transmission by using a bitmap field, to activate or deactivate duplication transmission of one or more packet data convergence protocol entities or radio bearers in the UE. Hence, activation or deactivation may be performed on the duplication transmission mode of one or more PDCP entities in the user equipment.