The invention provides a network flow control system which comprises a detecting unit, a judging unit, a determining unit and a first processing unit, wherein the detecting unit is used for detecting and counting point-to-point flows; the judging unit is used for judging whether an operation of discarding a data packet is taken when detecting that the flows exceed a threshold; the determining unit is used for receiving a judging result of the judging unit and determining a protocol type of the discarded data packet when judging that the operation of discharging the data packet is taken; and the first processing unit is used for taking the operation of discarding the data packet when judging that the protocol type of the data packet is a transition control protocol, and controlling a receiving end to send a message indicating buffer region congestion to a sending end. Correspondingly, the invention also provides a network flow control method. According to the technical scheme provided by the invention, when the flows exceed the threshold, while the operation of discarding the data packet is taken, the message indicating the buffer region congestion is sent to the sending end, so that the sending end knows that the receiving end is congested, and can be used for actively reducing the message sending rate, and ensuring that the inlet bandwidth is reduced while the outlet bandwidth is reduced.