Abstract: Based on the climate data of the agro pastoral zone in northern China,it selected five towns in the zone and analyzed the impact of the climate change and the variation of the primary climatic productivity from1956 to 2005,then analyzed the impact of the climate change on the Population Carrying Capacity.It showed that the temperature of agro pastoral zone was increasing yearly and the rainfall was decreasing,that was,the climate of the zone was getting dryer and hotter.Taking TongLiao of Inner Mongolia as an example and analyzed the variation of the Population Carrying Capacity from 1976 to 2005,it showed that the crop productivity was increasing proportional to the temperature and decreasing to the rainfall.The average annual temperature of TongLiao was increasing yearly,and the crop's productivity was increasing too.But the water was the key factor to the growth of crop,so the climate productivity would increase when the water was enough.The crop productivity would affect the yield and the population carrying capacity,so the study on the climate change in agro pastoral zone was very important.

Key words: Agro pastoral zone, Climate change, Population carrying capacity