A charging method includes: determining, by a control plane function entity (CP), that a data flow that is transmitted by user equipment (UE) on a first data session needs to be migrated to a second data session; charging, by the CP, the data flow on the first UP through a first charging session between the CP and a charging system; obtaining, by the CP, charging information of the data flow before the migration that is counted by the first UP; and determining, by the CP, a quota that is used for the data flow after the migration is necessary to be delivered to the second UP, and delivering the quota to the second UP, thereby charging a service data flow of a user in a case of migration between user planes.