Small satellites of distributed Space-Based Radar(SBR) are inevitably affected by the perturbation. The perturbation affects not only the satellite formation but also the sparse array beamforming of radar. From the satellite relative motion equations, by using orbital perturbation equations and introducing the formation configuration parameters in, simulations on distributed SBR satellite formation using space circle formation are performed according to the requirement that the spacing between the distributed SBR.and each member satellite should be small and stable. By using the simulation results of distributed SBR satellite formation under the influence of J2 perturbation, the beamforming simulations of distributed SBR and analysis of the beam pointing offset are given, which provide an important reference to the research on the beamforming technology of distributed SBR.