The present disclosure relates to a method and device for generating a protocol data unit (PDU) packet. The method includes: 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 and includes a preset field, and the preset field includes other fields than the FI field and the RF field that are redefined in a common packet header, or a target field that is newly added, a field length of the target field that is newly added being smaller than a total length of the FI field and the RF field.