A dynamic adjustment method for a protocol data unit, PDU, session, performed by a first core network device , the first core network device being a network data analytics function entity, the method comprising: obtaining (S201, S401) a first message sent by a first server , the first server being an application function entity or an application server, the first message indicating network resource information comprising at least one of a time information and a location information for a network slice or an application; obtaining (S201) a first parameter related to a quality of service based on the first message using a local mapping table; sending (S203) a second message to a second core network device , the second core network device being an access and mobility management function entity; wherein the second message carries first indication information, and the first indication information is used to indicate to a terminal device to collect statistics on a measurement result of the first parameter, the measurement result of the first parameter comprising a quantity of times of using the first parameter; obtaining the measurement result of the first parameter and obtaining (S403) a second parameter related to a quality of service by performing data analysis based on the measurement result of the first parameter, wherein the first parameter is determined as the second parameter when the quantity of times of using the first parameter in the measurement result exceeds a threshold; and sending (S207) a third message to the second core network device , wherein the third message carries the second parameter, and the third message is used to indicate to the second core network device to configure the second parameter by storing the second parameter in the second core network device . obtaining (S201, S401) a first message sent by a first server , the first server being an application function entity or an application server, the first message indicating network resource information comprising at least one of a time information and a location information for a network slice or an application; obtaining (S201) a first parameter related to a quality of service based on the first message using a local mapping table; sending (S203) a second message to a second core network device , the second core network device being an access and mobility management function entity; wherein the second message carries first indication information, and the first indication information is used to indicate to a terminal device to collect statistics on a measurement result of the first parameter, the measurement result of the first parameter comprising a quantity of times of using the first parameter; obtaining the measurement result of the first parameter and obtaining (S403) a second parameter related to a quality of service by performing data analysis based on the measurement result of the first parameter, wherein the first parameter is determined as the second parameter when the quantity of times of using the first parameter in the measurement result exceeds a threshold; and sending (S207) a third message to the second core network device , wherein the third message carries the second parameter, and the third message is used to indicate to the second core network device to configure the second parameter by storing the second parameter in the second core network device . <EOS>