Future geostationary operational environmental satellite (GOES) sounding (suggested hyperspectral infrared (IR) sounder on GOES-T) instrument could provide the accurate three dimensional temperature and moisture distribution with high temporal and spatial resolutions. To optimize the geostationary hyperspectral IR sounding instrument that meets the users' requirement, trade-off study has been carried out to balance the spectral coverage, spectral resolution, spatial resolution, temporal resolution and signal to noise ratio (SNR) for temperature and moisture soundings. Study has showed that hyperspectral IR sounder with properly selected spectral coverage, spectral resolution and SNR can achieve the accuracy of 1K for temperature and 10% for relative humidity in troposphere. The impact of temporal and spatial resolutions on sounding product is also studied. The great advantage of future geostationary hyperspectral IR sounding system over the current GOES Sounder in severe weather forecasting and nowcasting is demonstrated.