Abstract: The authors analyzed the climatic indices affecting winter wheat planting zone in China in this paper based on winter wheat growth characteristics,physiological mechanism of winter wheat and multiple crops system at regional and annual scale.After this,the main climate indices controlling winter wheat planting zone were identified by the maximum entropy (MaxEnt) method: duration in days of 0℃ to 7℃,the lowest monthly average temperature,potential evapotranspiration,and annual precipitation.At last,the Chinese winter wheat distribution-climate relationship was established and the changes of winter wheat planting zone and its high suitable area were given from 1961 to 2010.The results indicated that the threshold of the lowest monthly average temperature which determines the winter wheat planting zone was -12℃ to 15℃,the existence probability of winter wheat increases as the increases of the duration days of 0℃ to 7℃, and the existence probability of winter wheat was affected strongly by annual precipitation and the area with below 200mm of precipitation was none existence of winter wheat.The winter wheat planting zone in China shifted northward and westward from 1961 to 2010,and high climate suitable zone also shifted northward.Finally,the shifts may raise the utilization efficiency of climate resources,increase crop yield. By the results of study,the distribution of winter wheat could be predicted exactly from past to future,and it is helpful for improving layout of winter wheat planting zone in China and coping with the negative effects resulted from climate change.

Key words: Maximum entropy (MaxEnt) method, Winter wheat, Planting zone, High yield zone