Abstract: Based on the meteorological data in the Inner Mongolia autonomous region and Holdridge life zone classification climate system， we analyzed the change characteristics of temperature and precipitation from 1962 to 2011， compared the grassland types distribution during the 1962s （1962-1971） and the beginning of the 21st century （2002-2011）， explored the impact of climate change on potential distribution of grassland types in Inner Mongolia. The results showed that during 1962-2011， the annual and growing seasonal mean temperatures were risen significantly in the research area（P<0.05）， and the time of abrupt temperature change happened in 1990， in growing season the time delayed for 5 years than the annual mean temperature change. The precipitation change in forest steppe and typical steppe area showed a decreasing trend （2002-2006） after an increasing at first （1992-2002） （P<0.05）， while there was no significant change in desert steppe and desert area; The fluctuation of precipitation in the eastern area was greater than the western Inner Mongolia. The transition area of the typical steppe to desert steppe gradually expanded in past 50 years， while the forest steppe also had a change trend to typical steppe， contrast the temporal and spatial variation of temperature and precipitation with the distribution change of grassland types by climate distribution indicators， the impacts of precipitation change on grassland distribution was more significant than temperature in Inner Mongolia. The reducing of growing seasonal precipitation and resulting soil severe drought in a nongrowing season， and also increasing temperature made the higher evapotranspiration， would be impact the distribution of grassland ecosystem in Inner Mongolia．

Key words: Holdridge classification system, Grassland types change trend, Climate distribution pattern, Climate change trend