Abstract: 【Objective】 Increasing temperature in China significantly since the 1980s has become a consensus in the context of global climate change. How the change affected the agriculture or even the cropping system has attracted more and more attention of the government and scientists. In this study, the possible effects of climate warming on the countrywide northern limits of cropping systems, the northern limits of winter wheat and double rice, and the stable-yield northern limits of rainfed winter wheat - summer maize rotation in China from 1981 to 2007 were analyzed. And the possible changes of crop yield due to the changes of planting limits during the period from 1950s to 1981 and the period from 1981 to 2007 were compared and discussed. 【Method】 A recognized calculation method of agro-meteorological indicators were used in the study. The countrywide northern limits of cropping systems, the northern limits of winter wheat and double rice and the stable-yield northern limits of rainfed winter wheat–summer maize rotation were draw by ArcGis for two periods from 1950s to 1980 and 1981 to 2007, according to the indices of the climate zoning index of cropping system, winter wheat and double rice northern limits and stable-yield northern limits of rainfed winter wheat-summer maize rotaion. 【Result】 Compared with the results during the period from 1950s to 1980, the northern limits of the two-cropping system from 1981 to 2007 occurred significant spatial displacement in Shaanxi, Shanxi, Hebei, Beijing and Liaoning provinces and city. The northern limits of the three-cropping system occurred largest spatial displacement in Hunan, Hubei, Anhui, Jiangsu, and Zhejiang provinces. Without the consideration for variety and social economic changing, grain yield per hectare of main cropping pattern could increase about 54%-106% if the one-cropping system changed to two-cropping system, while increase about 27%-58% if two-cropping system is changed to three-cropping. The northern limits of winter wheat moved northwards and westwards to different degrees in Liaoning, Hebei, Shanxi, Shaanxi, Inner Mongolia, Ningxia, Gansu and Qinghai provinces,comparing with the results during the 1950s-1980 period. For example in Hebei province, northern limits of winter wheat moved north,leading to about 25% grain yield increase in the changing area if the cropping system is changed from spring wheat to winter wheat in one year. The northern limits of double rice cropping area in Zhejiang, Anhui, Hubei, and Hunan provinces moved northwards. Considering the heat resource, the change of limits can increase the grain yield. The stable-yield northern limits of rainfed winter wheat-summer maize moved southeastwards in most regions, mainly caused by the decreased rainfall during recent years in the study areas.【Conclusion】 During the past 50 years, the climate warming caused the northwards movement of the northern limits of cropping system, and the northern limits of winter wheat and double rice. The changes may increase the unit grain yield in the changing area. However, the stable-yield northern limits of rainfed winter wheat–summer maize rotation moved southeastwards due to the decreasing rainfall.

Key words: climatic warming, the northern limits of cropping system, the northern limits of winter whea, the northern limits of double rice, crop yields