To reduce the contradiction between the system space and the load-carrying capacity of a launching system and with the demand of reflectors with large apertures and high resolutions,a light-weight and flexible membrane reflector was developed and the precise control of the electrostatic stretched membrane reflector was realized.For a Ф300 mm electrostatic stretched polyimide membrane reflector coated with aluminium controlled by concentric annular electrodes,the control matrix for the reflector shape was determined by deducing the influence function of each electrode and the needed voltages on the distributed electrodes for the shape precise control were acquired by the least-square fitting on the basis of the approximate solution of the Poisson equation.The result by proposed method was compared with that obtained by ANSYS.It is shown that when the membrane center deflection is higher than 2.5 mm,the result is very different from that obtained by ANSYS,and the computed deflection deviates from an ideal deflection greatly.It cames to the conclusions that predicting and controlling the membrane shape of the small deflection exactly must use synthetically numerical computations and the least-square fitting,and also must find the membrane control matrix of the distributed electrode to solve the distributed voltages.