Space internet protocol SCPS-TP was used in satellite communication system. Based on the Vegas congestion control used in space internet protocol SCPS-TP,learning from the congestion window growth strategy in slow?鄄start phase of TCP Hybla protocol,modifying the threshold changes of congestion window and slow start when occurring packet loss and timeout,an improved Vegas strategy that is more fit for satellite communication link is presented. The improved strategy was simulated by NS2 software in GEO satellite communication link and compared with TCP Vegas and TCP NewReno. Results show the throughput of the proposed method in this paper gained a 15% improvement contrasting to TCP Vegas.