Provided are a data radio bearer control method, device, and system for a multi-connection system. The data radio bearer control method for a multi-connection system comprises: establishing a split protocol data unit session comprising M quality of service flows, the M quality of service flows being respectively established on N radio access network nodes, wherein one of the N radio access network nodes is a master node, and N−1 radio access network nodes other than the master node among the N radio access network nodes are secondary nodes, M and N are positive integers, and M≥2 and N≥2; and establishing a default data radio bearer for the split protocol data unit session, and configuring the default data radio bearer on any one of the radio access network nodes.