A case study of the impact of satellite sounding data on the numerical weather analysis and forecast has been done in the northern hemisphere operational numerical weather analysis and forecast system of National Meteorological Center, SMA. The thickness data from NOAA meteorological satellite, derived from satellite temperature soundings. have been used in the experiments. The results reveal that satellite soundings make an improvement on the numerical weather analysis and forecast. The impact of satellite soundings on the numerical weather analysis is related to the region and synoptic system, this impact mainly occurs in the sparse conventional data area and in the vicinity of strong weather systems. Also, the impact on numerical weather forecast is bound up with the evolution of synoptic systems, and this impact substantially occurs is developing systems.