中文摘要：

耕地压力指数是指最小人均耕地面积与实际人均耕地面积之比。文章通过对改革开放以来我国耕地压力指数的测算，发现耕地压力指数在1981年～1996年间呈下降趋势，主要原因是由于期间最小人均耕地面积减少速度大于实际人均耕地面积的减少速度；1996年后耕地压力指数整体处于上升趋势，这主要是由于期间实际人均耕地面积急剧减少所致。通过对2004年各省份压力指数的测算，发现有21个省份的耕地压力指数大于1，其中上海的耕地压力指数达到了2．84；即便是在无明显压力的5个省份中，其压力指数也均在0．78以上，区域耕地压力非常明显。导致各省份耕地压力指数过大的主要原因有3个：一是由于耕地大量被占用，实际人均耕地面积偏小而导致的压力指数过大；二是因单产水平过低而导致最小人均耕地面积偏大，从而使压力指数偏大；三是粮食主产区由于要承担国家商品粮任务，使区域粮食自给率过高，导致最小人均耕地面积过大，从而使耕地压力指数偏大。通过控制耕地面积减少速度、提高农业科技水平可以有效缓解耕地压力状况。

英文摘要：

The pressure index of cultivated land is the ratio of per capita minimal area of cultivated land and per capita actual area of cultivated land. The pressure index of cultivated land could reflect the status of pressure on cultivated land. The paper calculates the pressure index of cultivated land since China＇ s economic reform and opening-up using the pressure index model It is found that the pressure index decreased from 1981 to 1996 because the speed of per capita minimal area decrease is faster than that of per capita actual area. And the pressure index increase after 1996 because per capita actual area decreases rapidly. After calculation of pressure index in different provinces in 2004, there are 21 provinces＇ pressure index is more than land the pressure index inShanghai is up to 2.84. Even in the 5 provinces, the pressure index is all more than 0.78. The regional pressure is extremely obvious. There are three aspects of reason that cause various provinces pressure index on the high side. Firstly, cultivated land in some provinces is taken massively, which induces per capita actual area of cultivated land smaller then makes pressure index of cultivated land on the high side, such as Shanghai Zhejiang and so on. Secondly, per capita minimal area of cultivated land is on the high side because of low level of unit output which is limited of natural condition and agricultural science, such as Gansu, Shaanxi, Sichuan, Guizhou and so on. Thirdly, some provinces in which grain are producted mainly must undertake duty of national food security, which causes per capita minimal area of cultivated land on the high side, such as Hubei, Hunan and so on. It could relieve cultivated land pressure status by controlling the speed of cultivated land decreasing and enhancing the standard of agricultural science and technology.