The present invention provides a method for dynamic flow control, including the steps of: A. a subscriber equipment prioritizing an uplink data flow and sending the prioritized uplink data flow to an access node; and B. after receiving the data flow sent from the subscriber equipment, the access node classifying the data flow according to the priorities of the data flow in which data flows with the same priority are classified into the same flow tunnel, and performing flow control on a flow tunnel according to a flow control strategy delivered by a flow strategy control system. The present invention also provides a system for dynamic flow control, including a subscriber equipment, an access node and a flow strategy control system. The present invention could simplify the control complexity of an access node and provide a guarantee of QoS for legal data flows.