中文摘要：

测算和评价可利用土地资源（即后备适宜建设用地潜力）是开展主体功能区划的关键基础工作之一。在重点阐述主体功能区划可利用土地资源指标项涵义、功能、重要因素参数选择以及算法和技术流程的基础上,借助GIS空间分析技术,利用数字地形高程图（DEM）、2000年TM遥感影像解译土地利用图、县级行政区划图和国土部门土地利用变更数据,测算和评价了2005年我国可利用土地资源的数量和空间分布特征。研究结果表明：2005年我国可用于建设用地的可利用土地资源面积约28.54×10^4km^2,占全国陆地国土总面积的3.01%;全国人均可利用土地资源面积为0.34亩/人,其空间分布的基本特点是高值区相对集中于东北、华北北部、西北以及黄河中游地区,低值区成片集中于青藏高原和中、东部人口密集地区。

英文摘要：

Calculating and assessing available land（reserved construction land potential） is a key foundation of Major Function Oriented Regionalization.Under the background of land resources scarcity and the policy of cultivated land conservation,precisely evaluating land resources,especially reserved construction land of different regions seems to be one of important issues on how to put forward Major Function Oriented Regionalization.The article puts emphasis on definition,function,factor parameters,and arithmetic and technique course of available land for Major Function Oriented Regionalization.With the help of GIS spatial analysis techniques,using Digital Elevation Map（DEM）,TM remote sensing land use map of 2000,administrative map at county level and land use investigation data of 2005,the article calculated and assessed quantity and spatial differentiation of available land of China in 2005.The results show that： available land area for construction in China amounts to 28.54×10^4 km^2,which accounts for 3.01% of the total land area.Available land area per capita is 0.34 mu/person,and the main characteristics of spatial differentiation show that： the high value areas are concentrated in Northeast China,northern part of North China,Northwest China and the middle reaches of the Yellow River,while the low value areas are aggregated on the Qinghai-Tibet Plateau and densely populated areas of Central and Eastern China.Available land is a comprehensive index for assessing land capacity of population agglomeration,industrialization and urbanization in different regions.However,as a lot of factors are related to the index,one single index（available land area or available land area per capita） cannot precisely reflect all the contents of the index of available land.In the process of practical application,a few issues should be concerned.Firstly,available land index items consist of three factors： quantity,quality and scale of massing of reserved construction land.Available land area and available land area pe