In order to measure the baseline direction between small satellites,a measurement method is proposed using laser and telescopic pupil.The model for intersatellite baseline direction measurement is established based on Cartesian coordinates.Through analyzing the displacement of the target satellite projection to the reference satellite when the relative position between the two satellites changes,a measurement method where a retro-reflector array is placed on the target satellite is proposed.Then simulation is carried out with different orbit parameters.The measurement method proposed in this article is verified through experiments.And the results show that the method can implement the measurement of intersatellite baseline direction effectively.The expanded uncertainty is 7.4′(k=2).