Abstract: This paper is on mapping soil on the coast of Dongtai city, Jiangsu province. The results show that, because the mud coast deposits rapidly, the soil types (soil salt contents) change quickly and the orientation of soil plot in the field is difficult on the depositing coast, it is satisfactory to map soil on the coast. For correct and effective interpreting, it is necessary to choose suitable TM bands and suitable computer processing methods for combining false colour TM images. The research tells that the combinations of TM 5,4,3 and TM 5,4,2 after histogram being equalized, linear contrast streched and principal analyzed, are very beneficial for soil interpreting.