利用四川省SＲTM DEM 和种子植物分布数据，在ArcGIS 10． 1 软件平台下运用其强大的多源数据处理和空间分析能力，定量分析该省植物物种丰富度和地形单元多样性，并在区域尺度上对两者之间的关系进行研究。结果表明: 地形单元多样性指数介于0 ～ 0． 86 之间，指数较小的区域集中分布于成都平原、诺尔盖湿地和川西北高寒江源区等; 指数较高的区域主要分布于四川盆地的盆周山区和川西的纵向岭谷区; 全省种子植物物种多样性无论是在科、属、种阶元的丰富度，还是科、属的分化强度上，均表现出较为一致的空间分布格局和变化趋势，均呈现由盆地到盆周山区逐渐升高，再到高原( 川西高原和攀西高原) 又逐渐降低。总体上，种子植物物种丰富度随着地形单元多样性的增加而上升。研究结果初步揭示了区域尺度上植物物种多样性分布的地形背景，可为区域生态功能区划及流域生态保护与可持续发展提供科学的理论与数据支持。

The seed plants＇ species variety and topographic unit diversity in Sichuan Province was analyzed quantitatively and their regional relationship was studied based on SＲTM DEM data and plant distribution data by utilizing the powerful multi －source data processing and spatial analysis of ArcGIS10． 1 software． The results showed that the topographic unit diversity index in Sichuan Province is between 0 and 0． 86; the areas with lower value are located in Chengdu plain，Norgay wetland and alpine headwater area in northwestern Sichuan; the areas with higher value are located in the mountains around Sichuan Basin and the longitudinal Ｒang Gorge Ｒegion in western Sichuan． The variety of seed plants in Sichuan Province presents the same spatial distribution pattern and trend whether in the variety of family level，genus level，species level or in differentiation intensity in family level and genus level，increasing from the Sichuan basin to the mountains around the basin，and then decreasing again in alpines ( western Sichuan alpine and western Pazhihua alpine) ． In overall，the seed plants＇ variety increases with the increase of topographic unit diversity index． The results reveal the regional scale topographic background of distribution of various seed plants，which provides a scientific theory and data support for ecological function regionalization and sustainable development of the river
basin．