The present disclosure relates to a method and device for generating protocol data unit (PDU) packet. The method comprises acquiring a service data unit (SDU) packet, processing the SDU packet according to a size of a preset data packet, and generating a packet header and a data section of a PDU packet according to the processing result, the packet header and the data section constituting the PDU packet. The packet header omits a framing indication (FI) field and a resegmentation flag (RF) field but comprises a preset field, and the preset field comprises other fields except the FI field and the RF field that are redefined in a common packet header, or a target field that is newly added, the field length of the target field that is newly added being smaller than the total length of the FI field and the RF field.