Abstract: The performance of TCP (Transmission Control Protocol) congestion control algorithms over Iridium-like LEO (Low Earth Orbit) satellite networks is analyzed, including Reno, Newreno, SACK and Vegas algorithms. The focuses are on the whole network performance of various parameters and the average numerical value. The result of simulation shows that the Vegas algorithm is superior to other algorithms in average RTT, though there are no obvious differences among the four algorithms in the average throughput. By comparison with the result of simulation of single link, using the complete network topology to simulate TCP congestion control algorithms is more positive.