STMAS (Space and Time Multiscale Analysis System) is a next generation data assimilation system designed to improve forecasts and analysis. It uses a multigrid technique combining the advantages of EnKF and 4DVAR at different multigrid levels and improving the analysis. It is capable of analyzing multi-source data including radar, in-situ observation data and satellite data etc to obtain more objective atmospheric states initializing forecast model. In this presentation, we will introduce the STMAS System and present its analysis of satellite data. We apply STMAS satellite data assimilation in typhoon and/or hurricanes forecasts and estimate the satellite data impact on the forecasts.