The congestion control mechanism TFRC, which is widely used in current real-time streaming media, is analyzed in this paper. A proposal aiming at the requirement for short delay and jitter of real-time streaming media has been made to adjust to the transmit rate of the sender to the change of single trip delay jitter. Meanwhile, a dynamic adaptive method is used in the determination of the jitter threshold. The result of simulation indicates that with the improved algorithm the jitters has been reduced remarkably and other related QoS has also been improved.