With the modernized development of environmental science, weather observation and space detection and so on, it is an urgent requirement to carry out the research of portable and real-time supervised Fourier transform spectroscope in the leading basic research. A new micro-spaced modulated Fourier transform infrared spectroscope is proposed, without moving parts in this configuration. Thereinto, two multi-micromirrors are the key components in the interferometric system. The effect on the recovery spectra of the height of steps and the roughness of reflective surfaces in multi-micromirrors is simulated, and the height error of steps that can be tolerated by the system is ±0.18 μm, and the biggest roughness is settled at 150 and 200 nm. The multi-micromirror is fabricated by lithography-electroplating. The test result of the roughness of the reflectives surfaces of the multi-micro mirror (RMS) is 90.23 nm, and the height error of steps is ±0.1 μm, which meet the requirement of the design.