Abstract: In the case of the multi-point support for a thin mirror with a diameter of 600 mm, the paper studied the frequency-response of components’ surface, which was influenced by different support schemes. A one-dimensional beam model of dispersed support units had been established. The feasibility of the peak-to-valley(P-V), RMS values as support optimization objective functions was discussed. The result is that the values of P-V, RMS can not be the correct evaluation of the surface in the frequency domain response. Then, the frequency-response characteristics influenced by the interval and size of support units were analyzed. According to the results, the ideal support scheme is: the diameters of the center and lateral support units are 10 mm; the support unit interval is 125 mm.