The inductively coupled plasma chemical etching technology operating at atmospheric pressure is used to fabricate the optical mirror whose materials are fused silica, reaction-sintered silicon carbide (RB-SiC), Si. It is focused of the primary study on the removal function of the plasma torch on different samples. The Gaussian fitting full width at half maximum (FWHM) of the removal function is 18 mm. The removal rates are 10.86, 0.82, 1.51 μm/min respectively. A 100 mm caliber SiC mirror substrate is processed by using this technology, the error rate of the real obtained surface shape and virtual processed surface shape is 8.57%, and the error of converge rate is 4.7%. The experimental results show that the new technology has a potential application value on fabricating the large-aperture aspherical optical mirror in astronomy. So the inductively coupled plasma chemical etching technology operating at atmospheric pressure will have a promising foreground in the future.