Abstract: The water and heat conditions change resulted from climate change has strongly affected agricultural production, and famers take various kinds of measures to adapt to impacts of climate change. To further understand the effects of climate change on main grain crops and the adaptive measures taken by farmers, we analyzed changes in the planting structure of main grain crops based on the daily average temperature and the data from "China Agricultural Yearbook" published from 1980 to 2007 by National Bureau of Statistics as well as research results from literature. The results indicate that planting proportion changes of main grain crops were obvious on the nationwide scale from 1980 to 2007 as the result of the climate warming, the wheat planting proportion was more sensitive to climate change, and it fluctuated largely; the paddy rice planting proportion changed in opposite trends in northern and southern China, and its change has become slower; the corn planting proportion continued to increase, its change was enlarging; the planting structure of the three main grain crops (paddy rice, wheat and corn) all changed in 2000 with different increasing/declining trends. Furthermore, the crops ripe system and the multiple cropping index also changed obviously; the north boundary of crops planting has continuously moved northward. The winter wheat planting area in northern China in 2007 moved northward by nearly 100 km compared with the 1960s. The paddy rice planting area has greatly expanded in Heilongjiang Province, where the paddy rice has dominated in the original corn planting areas.

Key words: climate change, planting structure, wheat, corn, paddy rice