A protocol stack adaptation apparatus for compressing at least one wireless transmission protocol packet, wherein the apparatus comprises an acquiring unit, a detection unit, an adaptation unit, a sending unit, a receiving unit, a storage unit, a determining unit, and a counting unit, wherein the acquiring unit is configured to acquire a first wireless transmission protocol packet; the detection unit is configured to detect, by using a first preset detection rule, whether the first wireless transmission protocol packet carries user data; the adaptation unit is configured to, if the first wireless transmission protocol packet carries user data, adapt the first wireless transmission protocol packet to a corresponding first standard Internet Protocol, IP, data packet; the sending unit is configured to, if the first wireless transmission protocol packet carries user data, send the first standard IP data packet to a network transmission optimization, NTO, device for processing; the receiving unit is configured to receive a second standard IP data packet sent by the NTO device after processing N received first standard IP data packets, wherein N ≥ 1, and N is an integer; the adaptation unit is further configured to adapt the second standard IP data packet to a corresponding second wireless transmission protocol packet; the acquiring unit is further configured to: if the first wireless transmission protocol packet carries user data, acquire a mapping relationship between first transmission network layer header information of the first wireless transmission protocol packet and quintuple information of the first standard IP data packet; the storage unit is configured to store the mapping relationship; the determining unit is configured to: after the receiving unit receives the second standard IP data packet sent by the NTO device and before the adaptation unit adapts the second standard IP data packet to the corresponding second wireless transmission protocol packet, determine, according to quintuple information of the second standard IP data packet and the mapping relationship, N pieces of first transmission network layer header information corresponding to the quintuple information of the second standard IP data packet; the determining unit is further configured to: if the N pieces of the first transmission network layer header information comprise IP headers, User Datagram Protocol, UDP, headers, and general packet radio service technology GPRS Tunneling Protocol-User Plane, GTP-U, headers, and S identifiers of the GTP-U headers in the N pieces of first transmission network layer header information are 1, determine whether transmission network layer session information corresponding to the N pieces of first transmission network layer header information is stored, wherein the transmission network layer session information comprises a GTP-U serial number; the counting unit is configured to: if the storage unit stores the transmission network layer session information corresponding to the N pieces of first transmission network layer header information, increase the GTP-U serial number in the transmission network layer session information corresponding to the N pieces of first transmission network layer header information by 1; the storage unit is further configured to: if no transmission network layer session information corresponding to the N pieces of first transmission network header information is stored, store the transmission network layer session information corresponding to the N pieces of first transmission network layer header information, wherein the GTP-U serial number in the transmission network layer session information is a minimum serial number of GTP-U serial numbers of the GTP-U headers in the N pieces of first transmission network layer header information; and the determining unit is further configured to determine, according to the GTP-U serial number in the transmission network layer session information corresponding to the N pieces of first transmission network header information and the N pieces of first transmission network header information, transmission network layer header information corresponding to the second standard IP data packet.