A method for implementing usage monitoring control, comprising: prestoring a total allowanced usage shared by multiple users in a Subscription Profile Repository, SPR; setting, by the SPR, an allowanced usage threshold according to a request from a first Policy and Charging Rules Function, PCRF, and distributing, by the SPR, the set allowanced usage threshold to the first PCRF; making, by the first PCRF, a usage monitoring policy according to the obtained allowanced usage threshold; deducting, by the SPR, a consumed usage from the total allowanced usage shared by the multiple users after receiving a usage report from the first PCRF; wherein different PCRFs are selected for the multiple users, and the first PCRF is selected for a first user, while a second PCRF is selected for a second user; when the first user in the multiple users requests to establish an IP-Connectivity * Access Network, IP-CAN, session, the step of obtaining, by the first PCRF, the allowanced usage threshold comprises: including, by the SPR, the allowanced usage threshold in a subscription information of the users and returning the subscription information to the first PCRF; wherein the allowanced usage threshold is a first allowanced usage threshold; and the first allowanced usage threshold is smaller than or equal to the total allowanced usage, the first allowanced usage threshold is for all service data flows of a certain IP-CAN session or for one or more service data flows in a certain IP-CAN session; when the second user in addition to the first user in the multiple users requests to establish an IP-CAN session, including, by the SPR, a second allowanced usage threshold in the subscription information of the users and returning the subscription information to the second PCRF, wherein a sum of the first allowanced usage threshold and the second allowanced usage threshold is smaller than or equal to the total allowanced usage. prestoring a total allowanced usage shared by multiple users in a Subscription Profile Repository, SPR; setting, by the SPR, an allowanced usage threshold according to a request from a first Policy and Charging Rules Function, PCRF, and distributing, by the SPR, the set allowanced usage threshold to the first PCRF; making, by the first PCRF, a usage monitoring policy according to the obtained allowanced usage threshold; deducting, by the SPR, a consumed usage from the total allowanced usage shared by the multiple users after receiving a usage report from the first PCRF; wherein different PCRFs are selected for the multiple users, and the first PCRF is selected for a first user, while a second PCRF is selected for a second user; when the first user in the multiple users requests to establish an IP-Connectivity * Access Network, IP-CAN, session, the step of obtaining, by the first PCRF, the allowanced usage threshold comprises: including, by the SPR, the allowanced usage threshold in a subscription information of the users and returning the subscription information to the first PCRF; wherein the allowanced usage threshold is a first allowanced usage threshold; and the first allowanced usage threshold is smaller than or equal to the total allowanced usage, the first allowanced usage threshold is for all service data flows of a certain IP-CAN session or for one or more service data flows in a certain IP-CAN session; when the second user in addition to the first user in the multiple users requests to establish an IP-CAN session, including, by the SPR, a second allowanced usage threshold in the subscription information of the users and returning the subscription information to the second PCRF, wherein a sum of the first allowanced usage threshold and the second allowanced usage threshold is smaller than or equal to the total allowanced usage.