中文摘要：

我国海域中面积在500m^2以上的海岛6500多个，12个海岛县共有海岛1738个，占全国海岛的27％，占全国有人居住海岛（433个）的40．6％。12个海岛县共有岛陆面积4087km。，占全国海岛面积的（包括台湾岛、海南岛）5．1％。海岸线总长4411km，占全国岛屿岸线（14000km）的31．5％。我国12个海岛县分散分布在渤海、黄海、东海和南海四大海域中，由于所处的海域位置、海洋与岛陆资源丰度以及受市场机制、社会经济状况、资源开发力度与行政区经济的影响，各海岛县经济上存在着明显的差异。根据海岛县的区位特点以及资源的开发，海岛经济有了较快的增长。12个海岛县的国民生产总值1980年为12．05×10^8元，到2005年达到656．42×10^8元；人均GDP，1980年为473．5元，2005年为22325元，分别递增17．3％和16．7％。国民经济三次产业结构从1980年的40．7：34．9：24．4，到2005年为19．4：41．3：39．3。根据12个海岛县三次产业的结构变化，应用“三轴图方法”，绘制海岛县产业结构演进过程图。应用主成分分析方法，对各海岛县的经济综合实力进行了评估研究并进行排序，从而为各海岛县经济的进一步持续发展提供依据。

英文摘要：

There are more than 6,500 coastal islands with 500m^2 more area in China. These twelve island counties boast 1 738 islands, taking up 27% of the country＇s total. Among these islands, 176 are inhabited, accounting for about 40.6 % of the total. The land area of those islands amounts to more than 4 087 km^2, occupying about 5.1% of the country＇ s total coastal islands （ including Taiwan and Hainan islands）. The length of coastline totals 4 411 km, accounting for 31.5 % of the country＇ s total island coastline（ 14 000km）. These 12 island counties are scattered in Bohai Sea, Yellow Sea, East Sea and South Sea. The differences in economic development level among these 12 island countries exist significantly because of their disparity of location, resources render degree, market mechanism, socioeconomic condition, resource development capacity and administrative capacity. The island economies have witnessed a faster increase in the past decades. The GDP in these 12 island countries totaled 12.05 billion yuan in 1980 and reached 656.42 billion yuan in 2005. Per capita GDP totaled 473.5 yuan in 1980 and 22 325 yuan in 2005. The growth rates of GDP and per capita GDP were 17.3% and 16.7%. In 1980, the ratio of primary, secondary and tertiary industries was 40.7 to 34.9 to 24.4 and it was 19.4 to 41.3 to 39.3 in 2005. According to the change of industry structure of these 12 island counties, this paper described the evolvement process of industry structure in these islands counties by using the method of ＂three-axismap＂. In order to reflect the differences between different island counties, the paper used the method of principal component analysis to give an evaluation and classification of comprehensive strength of island counties. This will provide basis for the further sustainable development of the island county economy.