中文摘要：

本文以北京市平谷区为例，利用1993年、2008年两期土地利用现状图，从数量结构、空间格局和类型转换三个角度对平谷区土地利用的动态变化情况进行了定量分析。结果表明：①15年来，平谷区耕地面积锐减，园地面积大幅增加，城乡建设用地逐年增加；②土地利用变化的强度和方向在不同地貌分区存在明显差异，山区、半山区受农业结构调整和生态退耕政策影响，耕地流失最严重，主要转为园地和林地，而在平原区，主要是建设占用导致耕地减少；从山区、半山区到平原区建设用地面积增加量依次增大；③在土地利用类型转换上，主要表现为耕地转为园地、林地和城镇村及工矿用地，林地转为园地，以及草地转为林地；园地的增加主要来自农业结构调整，新增建设用地主要分布在平原区，来源于耕地。因此，协调经济发展与农地保护间的矛盾，是平谷区社会经济发展中必须重视和解决的问题；继续加强生态保护，以保障平谷发展服务首都北京的功能，实现自身社会经济的可持续发展目标。

英文摘要：

Jointly affected by urban expansion, industrial relocation, and other effects from downtown, land use change in metropolitan fringe areas is marked. Pinggu District is one of the 18 districts in Beijing, functioning as an agricultural supply base. However, as the economy and industry develop, allocation of land resources becomes increasingly complicated. Analyzing land use change during the past years and examining land use trends are of importance to future development. Using land use maps of Pinggu District in 1993 and 2008, land use dynamic change was analyzed in this paper from aspects of quantity, spatial pattem, and transformation. With natural conditions of Pinggu and socio-economic statistics from Statistical Yearbook, some phenomena were explained. Results indicate that the area of arable land decreased rapidly from 1993 throughout 2008, orchard land increased significantly, and the built-up land increased gradually. Based primarily on elevation and slope, the study district was generally partitioned into three township-based landform areas, i.e., the mountainous area in the north and the east, semi-mountainous area in the centre and the west, and plains in the southwest. The land-use pattern and the spatial distribution of land use change varied significantly in different landforms. In mountainous and semi-mountainous areas, due to agricultural structural adjustment and the Sloping Land Conversion Program, arable land decreased greatly, which were mainly transformed into orchard land and woodland. While in the plain area, expansion of built-up land was the major reason for loss of arable land. A large quantity of new construction land appeared in the plain area, particularly in Pinggu town. There was less change taking place in mountainous and semi-mountainous areas. As to transformation of land-use types, only 1/3 arable land in 1993 was preserved from the matrix of land-use change, most of which was transformed into orchard land, woodland, and built-up land. Woodland was transformed into orchard, gras