Abstract A reliable and autonomous navigation system is crucial for the achievement of high survivability of spacecraft. As a novel autonomous navigation system, inertial/spectral redshift(INS/SRS) integrated navigation system can correct the navigation error of INS through redshift and direction vector information from celestial body. However, Since SRS need to obtain the position measurement by integrating the velocity information of the spacecraft, the position error from INS/SRS is diverged. Thus, this paper investigates a direction vector assisted INS/SRS integrated navigation system for the spacecraft. In this paper, the relationship among the position of spacecraft, redshift and direction vector from celestial body are investigated. And then a direction vector assisted SRS is proposed which can solve the position information of spacecraft directly by redshift and direction vector information. Finally, the direction vector assisted SRS has been combined with INS as the direction vector assisted INS/SRS integrated navigation system. Simulations and comprehensive analysis have demonstrated the proposed integrated navigation system has better navigation performance than INS/SRS integrated navigation system.