Provided are an entity configuration method, device and system, a gNB-CU-User Plane (gNB-CU-UP). The entity configuration method includes: acquiring, through an Xn interface, specified information for configuring each packet data convergence protocol (PDCP) entity for processing a data radio bearer, where the Xn interface is an interface between a gNB-CU-Control Plane (gNB-CU-CP) and a gNB-CU-UP; and configuring the each PDCP entity according to the specified information. The present disclosure solves the problem of how to implement configuration of a gNB-CU-UP protocol entity and achieves centralized traffic convergence.