Abstract: With the development of space communications and the increasing number of satellites, routing between satellites in the space DTN (delay-tolerant network) network becomes more and more important. Thus, a large number of complex satellite network routing strategies have been proposed. Considering the regularity and predictability of space DTN networks, this paper examines the contact graph routing (CGR) protocol based on satellite regularities; the simulation tool ONE is adopted to simulate real satellite network scenarios. Simulation results show that the delivery ratio, average delay, and the network overhead ratio of CGR are better than those of the Epidemic and Prophet routing strategies.