Abstract: In consideration of Time-varying and Three-dimensional characteristics of the formation flying InSAR satellites system parameters,a new method derived from time-vector analysis for generation of elevation information was presented.The calculation and simulation programs were also developed.The relations between the ground targets' absolute altitude and system parameters in a single flight period were analyzed in detail.As a result of vector resolution,an analytical method using matrixes to indicate system parameters' error propagation coefficients was established.The analysis of variation regularity of the ground target absolute altitude,followed with the continuous alteration of the formation flying satellite relative orbital configuration,was carried out by putting the processing module of the system parameter error propagation coefficients matrixes into the time-vector analysis model.The results provide theoretical foundation for system key techniques extraction.