Current presentation demonstrates technical use of ENVI GIS for processing Landsat TM images. Spatial analysis performed by ENVI GIS enabled to process satellite images for urban studies. A case study is Taipei city, Taiwan, China. Spatio-temporal analysis was applied to Landsat TM images taken at 1990 and 2005. Built-in functions of the mathematical K-means algorithm enabled to classify Landsat TM images and to derive information on land cover types. Image classification was used to analyse land cover changes in Taipei which includes built-up areas and natural green areas. Results of image processing and spatial analysis show changes in structure, shape and configuration of urban landscapes in Taipei since 1990. Areas occupied by human activities increased, while natural landscapes undergone modifications. Changes in urban landscapes of Taipei are caused by the increased relocation of population, urbanization and occupied lands for urban needs.