To increase working efficiency of airborne short wave infrared (SWIR) push-broom spectral imagers and acquire wider coverage, a fore-optics with 90° field of view (FOV) is researched. A new-style tilted component reflective system is put forward to avoid descending of transmittance at long waveband in traditional refractive SWIR fore-optics working in 1～2.5 μm. Three-order aberrations correction of tilted component system is briefly introduced. Based on initial configuration solving, a 15 mm focal length, 1/3.5 relative aperture, 90° FOV reflective fore-optics with tilted components is designed, whose distortion is optimized while remain telecentric. Its average modulate transfer function (MTF) at Nyquist frequency is more than 0.68, and relative illumination of margin field achieves 88%. Besides, there is no transmittance descending caused by material absorption. Push-broom image with fore-optics′ distortion is simulated. The optical design can be applied in SWIR spectral imagers with wide FOV and enhance system′s detection sensitivity extremely.