A data transmission control method, apparatus and system are provided. A radio communication node receives a data packet sent by a base station, where the data packet is generated by using a Packet Data Convergence Protocol protocol data unit PDCP PDU of the base station. The radio communication node acquires the PDCP PDU, which is used as a Radio Link Control service data unit RLC SDU, in the data packet. The radio communication node sends data generated by using the RLC SDU to a user equipment, where a user plane connection is established between the radio communication node and the user equipment, and a control plane connection is established between the base station and the user equipment.