This Paper investigates the TCP (Transmission Control Protocol) friendliness of multicast videoconferencing system s. Through the analysis and simulation experiments it is shown that the slow response to network state changes and the fixed rate adjustment Process lead to TCP unfriendliness in the bandwidth sharing. Therefore, this Paper proposes a new TC P friendly flow control algorithm called TFR C-IV S flow control algorithm for the current best-effort Internet. TFRC-IVS (TCP-Friendly Rate Control- INR. IA Videoconferencing System) algorithmutilizes TCP friendly control function derived from complex TC P model to calculate TC P friendly sending rate. Simulation results show that TFRJC-IV S flow control algorithm improves the smoothness of transmission rates and converges quickly to the stable sending rate. In addition, the TCP friendly control function in TFRC-IV S flow control algorithm ensures the TCP friendliness of video flows and fair bandwidth allocation with TC P flows, which the traditional static rate adjustment algorithm lacks.