A parameter configuration method, applied to a first core network device, wherein the method comprises: sending parameter configuration information to a relay terminal device, wherein the parameter configuration information is used for configuring Quality of Service, QoS, parameters between the relay terminal device and a remote terminal device when a reflective QoS mechanism has been enabled; the parameter configuration information comprises a QoS flow identifier, QFI, bound to a Policy and Charging Control, PCC, rule, and QoS parameters corresponding to the QFI; the sending the parameter configuration information to the relay terminal device, comprises: receiving, by the first core network device, the PCC rule from a third core network device, wherein the PCC rule comprises first reflective indication information, and the first reflective indication information is used to indicate whether to enable the reflective QoS mechanism, wherein the third core network device provides control plane functions; determining, by the first core network device, a state of a configuration corresponding to the PCC rule; and sending, by the first core network device, the parameter configuration information to the relay terminal device, when the first reflective indication information is used to enable the reflective QoS mechanism, and the configuration corresponding to the PCC rule is used for relaying, wherein the configuration corresponding to the PCC rule indicates a Packet Data Unit, PDU, session corresponding to the PCC rule. sending parameter configuration information to a relay terminal device, wherein the parameter configuration information is used for configuring Quality of Service, QoS, parameters between the relay terminal device and a remote terminal device when a reflective QoS mechanism has been enabled; the parameter configuration information comprises a QoS flow identifier, QFI, bound to a Policy and Charging Control, PCC, rule, and QoS parameters corresponding to the QFI; the sending the parameter configuration information to the relay terminal device, comprises: receiving, by the first core network device, the PCC rule from a third core network device, wherein the PCC rule comprises first reflective indication information, and the first reflective indication information is used to indicate whether to enable the reflective QoS mechanism, wherein the third core network device provides control plane functions; determining, by the first core network device, a state of a configuration corresponding to the PCC rule; and sending, by the first core network device, the parameter configuration information to the relay terminal device, when the first reflective indication information is used to enable the reflective QoS mechanism, and the configuration corresponding to the PCC rule is used for relaying, wherein the configuration corresponding to the PCC rule indicates a Packet Data Unit, PDU, session corresponding to the PCC rule. receiving, by the first core network device, the PCC rule from a third core network device, wherein the PCC rule comprises first reflective indication information, and the first reflective indication information is used to indicate whether to enable the reflective QoS mechanism, wherein the third core network device provides control plane functions; determining, by the first core network device, a state of a configuration corresponding to the PCC rule; and sending, by the first core network device, the parameter configuration information to the relay terminal device, when the first reflective indication information is used to enable the reflective QoS mechanism, and the configuration corresponding to the PCC rule is used for relaying, wherein the configuration corresponding to the PCC rule indicates a Packet Data Unit, PDU, session corresponding to the PCC rule.