中文摘要：

依据县域农业统计数据，以单位耕地面积的粮食产量作为衡量耕地基本生产力的指标，对比分析了1985—1987和2002—2004两个时段的耕地生产力空间变化情况。结果表明：①过去20年全国大部分地区耕地生产力普遍提高，在农牧交错带及其以西地区耕地生产力增加幅度尤为显著，这些地区耕地生产力的提高对全国粮食总产量增加具有重要意义；②受中国降水空间分异影响，耕地生产力的东西差异依然显著，农牧交错带耕地生产力最低；农牧交错带以东，自西北向东南耕地生产力逐渐增高，耕地生产力区内差异在2002～2004年已表现得不踞显；农牧交错带以西，耕地生产力相对增长速度明显快于东侧和农牧交错带；东部地区，由于北方耕地生产力增幅明显，以温度为主导的南北差异已经缩小。

英文摘要：

Based on the statistic data of agriculture in county-resolution for the time period of 1985 - 1987 and 2002 - 2004, the changing regional distribution of grain productivity in China in recent 20 years has been examined in this paper. It is found that, 1 ） grain productivity indicated by grain yield per unit cropland has increased in most parts of China, especially in the west to the farming-grazing transitional zone, which has played more important role on total grain yield increase in the past 20 years in China. 2） the differences of a grain productivity dominated by rainfall between the eastern and western China have remained obviously up till now. But the southnorth difference of grain productivity dominated by temperature in the eastern China has reduced for the sensitive increase in grain productivity in the northern China. The lowest grain productivity zone is located in the farminggrazing transitional zone where the precipitation is 250 -400 mm. East to the lowest zone, grain productivity has raised gradually from the northwest to the southeast which may be divided in higher grain productivity zone and the highest grain productivity zone. But the gradation of grain productivity in the east became less obvious in the period of 2002 - 2004. West to the lowest zone, named the lower grain productivity zone, the relative increase of grain productivity was faster than that in the lowest zone and east to the lowest zone. 3 ） The area of cultivated land has expanded obviously in the western China, where the grain productivity is lower but increased fasty. While high quality cultivated lands reduced. There are positive impacts of climate change on the increase of grain productivity in Gansu and Xinjiang region, the middle-east of Inner Mongolia and Northeast China, where the temperature has risen significantly and the precipitation in most regions of western China has increased slightly in recent 20 years. 4） The regions, of which the grain productivity ranks the top and bottom in China, both have the highe