A Media Access Control protocol data unit processing method includes: obtaining a Media Access Control (MAC) protocol data unit (PDU), where the MAC PDU includes N sub-PDUs, each sub-PDU includes a logical channel identifier (LCID), the N sub-PDUs are arranged in a first sequence, and N is a positive integer; parsing the N sub-PDUs according to the first sequence, and when a first sub-PDU is parsed, stopping the parsing and reserving a parsed second sub-PDU, where the second sub-PDU includes at least one sub-PDU before the first sub-PDU in the N sub-PDUs in the first sequence, and a value of an LCID included in the first sub-PDU is a specified reserved value. In this way, a manner for processing a MAC PDU can be provided when a value of an LCID is an invalid value or a reserved value.