In order to better serve the ecological construction in Inner Mongolia,provide the evolution process of regional climate background,we used humidity index method to analyze the types of dry and wet climate change in Inner Mongolia during 19812010. The results show that half arid area,arid region and subhumid area or humid area were 343 090 km~2,388 035 km~2 and 411 819 km~2,respectively,in Inner Mongolia in recent 30 years. Half arid area + arid region + extremely arid areas during 20012010 were 1.3 times of those during 19912000,subhumid area + humid area decreased by 0.5 times; comparison of dry and wet climate type with historical precipitation distribution shows that arid region and below were close to the area with more than 200 mm of precipitation; humid region were close to area with more than 400 mm of precipitation in northeast of Inner Mongolia; the most widespread half arid areas were affected by the temperature and precipitation,which had nothing to do with the rainfall distribution; correlation analysis indicated that the temperature presented the significantly increasing trend,and precipitation decline resulted from the climate fluctuation in nearly 30 years; correlation coefficient of regional net primary productivity and precipitation is 0.930 0,and correlation coefficient of regional net primary productivity and temperature is only 0.270 0; the interdecadal changes indicated that NPP significantly decreased during 20012010,presenting the stepped down from northwest to southeast,the area greatly influenced mainly distributed in the typical steppe and meadow steppe in western of Hulunbuir City,at the same time,NPP significantly decreased in Chifeng City and Tongliao City in recent 20 years,NPP significantly decreased in eastern district area,NPP fluctuated in the western area.