A quality of service (QoS) parameter processing method and a system, where the method includes a session management function device obtaining a core network (CN) packet delay budget (PDB) between a first access network device and a first user plane function device, and sending the CN PDB to the first access network device via a context update response message, where the first access network device is a target access network device serving a terminal device after a handover. After receiving the CN PDB, the first access network device determines an access network (AN) PDB between the terminal device and the first access network device based on the CN PDB and an end-to-end PDB between the terminal device and the first user plane function device, and then schedules an air interface resource between the terminal device and the first access network device based on the AN PDB.