In the secondary mirror mounting procedure of a space-borne remote sensor, the method of clearance fixation with auxiliary adhesive is used to fix the mirror usually, which will cause the asymmetric aberration and influence on the imaging quality when the temperature is changed. Moreover, variation of the surface shape is irreversible due to the adhesive layer come from nonlinear materials. To improve the imaging quality and structure reliability, this paper proposed a zero clearance support method based on the lowest potential energy principle . Via the method of interference fixation with flexible blocks, the astigmatism aroused by non-symmetrical stress was avoided theoretically, and the irreversible problem was solved. The appropriate interference value (0.03 mm) was obtained by the finite element analysis. By using the interference value, both gravity and temperature variation(±4 ℃) were considered and the surface shape test was performed using an interferometer. Experiments show that the RMS value of the surface shape is 0.018λ, which meets the design requirements (RMS value≤0.02λ). obtained results demonstrate that the zero clearance support method for the circle mirrors can relieve the adverse effect of the surface shape caused by temperature variation.