Abstract: This paper develops the method of delimiting vulnerable scope and assessing coastal vulnerability through the observation and sampling in the field and applying the means of remote sensing and GIS, which can be suitable for great river delta and coastal plains with great area, relative complex micro geomorphology and the protection of seawall. The vulnerable scope should include inundated tidal flats due to sea level rise, coastal lowlands of soil salinization caused by rising phreatic water level and the area directly harmed by exacerbating storm surges due to sea level rise. The Jiangsu Coastal Plain is low flat, where considerable part of habitable lands are below local mean high tidal level (3 m above sea level) and depend on the protection of low standard seawall. So this area is the most vulnerable to sea level rise and exacerbating coastal hazards. Applying above mentioned method, the coastal vulnerability of Jiangsu Coastal Plain to relative sea level rise (approximately 50 cm up to 2050 yr) and exacerbating storm surge has been assessed. The results show that, up to the 2050 yr, the Jiangsu Coastal Plain will probably loss 12 8% of tidal flats (about 6.7?10⁴hm²) and 7 7% of cultivated land (about 8 2 10⁴ hm²). Meanwhile, 2 0% of population, 5 9% of original value of fixed capital, 4 1% of GDP (Gross Domestic Product), 53 3% of salt industry and 6 8% of aquiculture respectively will be affected, due to coastal environmental change. The coastal vulnerability degree(CVD) of the whole area belongs to medium grade (the index between 0 and 1 is 0 56). In view of different coast sections, CVD of the northern area of Guanhe River Mouth and Abandoned Huanghe River Delta belong to high grade (the indexes reach 0 81 and 0 63 respectively), these of the northern part of Middle Coastal Plain and the northern part of the Changjiang River Delta belong to medium grade too (the indexes are 0 45 and 0 46 respectively). that of the southern of Middle Coastal Plain belongs to the lowest grade (the index is 0 31).

Key words: coastal vulnerability assessment, vulnerable scope, coastal environmental change, Jiangsu Coastal Plain, sea level rise