Abstract:

Systematical constitution of coastal earlywarning system in tidal area was discussed in this paper.Primary research on choosing index of earlywarning and establishing power of weight and the interference parameter of subsystem was carried.With Jiangsu marine development and the implementation of the strategy for the eastern Jiangsu，Yancheng has become an emerging industrial development zones，and industrial change intensified.Meanwhile，the impact on the environment has become more striking.By using of principal component analysis，second curve forecasting method，expert fuzzy prediction method and other methods quantitative study of Yancheng Coastal Zone environmental indicators and subsystem level weights were done from 2006 to 2015，at the same time early warning and forecast of the impact on the environment of Yancheng Coastal Zone were established.It suggests that Yancheng social environment indexes increase gradually，and it has entered Light District in 2003.The per capita income index had risen from 011 in 1995 to 0789 in 2005，at that time the tertiary industry index has made significant progress.It is not optimistic that environmental pollution index dropping down from 09% in 1995 to 05% in 2005，and has reentered the heavy warning area.A warning mode on trial of coastal newly development area was established and an experiment was carried in Yancheng coast.Result revealed that even no heavy warning occurred，but Yancheng was always in medium warning level，except for occasionally slight warning.The environmental pressure on Yancheng is still rigorous.So Yancheng City should take reasonable development mode and control total development strength to attain harmonious and sustainable development of environment and economy.

Key words: coastal district, earlywarning, mode, Yancheng City, index system