Abstract: Configuration design is of great importance to the formation flying InSAR satellites system.To achieve specific spatial baseline form when the satellites are flying over the specific Earth surface,the formation configuration is the only variable which can be designed freely,while other parameters are restricted by many limiting factors.The formation flying model based on orbit perturbation solution was studied.The orbit design constraint conditions and objective of formation flying InSAR satellites were analyzed.Four two-satellite formation proposals and comparisons of their elevation generation performances were presented.The influence of the earth flattening perturbation to the formation configuration and the InSAR measurement performance were also described.