Natural disasters, human displacement and human migration are associated with each other. Increased frequency and severity of natural disasters over the past recent years in Bangladesh, are not only displacing people but also exposing to enhanced unplanned urbanization by increasing the amount of disaster migrants to Dhaka city. To know the amount of disaster migrants, most disaster affected areas and spatial distribution of disaster migrant s settlements, this paper aims at estimating the number of natural disaster induced migrants in Bangladesh and to show the spatial distribution of disaster migrants in slum settlements of Dhaka. This paper also aims at to monitor different hazards and disasters by applying disaster mapping in the pre and post management of any disaster event. Using GIS and Remote Sensing technology, the study compared existing satellite image with previous satellite image of the same location and tried to estimate disaster affected areas and number of displaced people under different disaster events. The movements of disaster migrants are presented by different maps from the estimated number of disaster migrants as a form of migration mapping.