Abstract: On the basis of space baselines in relative motion coordinate(rectangular Cartesian coordinate),the determination principle of the configuration angle on formation design of distributed SAR systems is proposed.From the view of InSAR imaging geometric,the height measurement and its error function are developed.And,the space baseline vector measurement precision is given,the function between system configuration angle and height measurement precision is presented in the conditions of the fixed effective baseline and the fixed vertical baseline.Simulation results show that the system configuration angle has little effect on height measurement while the effective baseline is fixed.And in order to make the system optimal precision,the system configuration angle must be equal to the radar beam look angle for the fixed vertical baseline.