The embodiment of the invention discloses a route determining method based on a satellite network. The route determining method comprises the following steps of enabling a source satellite to send N test data packets to a target satellite; enabling the target satellite to determine the passing path of the test data packet and the fitness value of the path according to the time of reaching next hop satellite and the target satellite recorded in the data test packet; according to each determined path and the fitness value thereof, determining the route information from the source satellite to the target satellite. By adopting the plan, the route determining method has the advantage that when a satellite network has jam or a node fault, the re-calculation of all route information in the satellite network is not needed, so that the calculation quantity of the determined route information is reduced.