Impervious surface can be used as an indicator in assessing urban environments. In this study, we have used method of remote sensing through the impervious surface to detect urban area in Hochiminh city with good accuracy above 96%. The high accuracy of the measurements come from the application of techniques such as extraction of training samples based on brand ratios, supervised classification in combination with suplement GIS data. This method, in combination with the Landsat image database, can be ultilized in monitoring the development of urbanization in Hochiminh city.