Along with the global climate change,plant phenology has also changed.In order to analyze the response of phenology for Leymus chinensis steppe in Inner Mongolia to climate effectively,we first used the Savitzky-Golay function to reconstruct the National Oceanic and Atmospheric Administration Normalized Difference Vegetation Index (NDVI) time series for the selected test pixels,then used moving average methods to derive the phenology for Leymus chinensis steppe.The performance of the methods for green-up date and the end of season date identification were verified by the ground observation samples.The phenology dates identified by the moving average method using the reconstructed NDVI time series,were well consistent with the observed ground phenology data.The correlations coefficient (r) of the phenology derived from remote sensing and the ground observation were between 0.43 and 0.63,while the significant level (P) were between 0.005 and 0.05.The differences of the phenology derived from remote sensing and the ground observation were between 10 and 30 days.On this basis,we acquired phenology stages (e.g.green-up dates and end of season dates) and the length of the growing season at each weather station,and analyzed their response to climate change combing with climate data (temperature and precipitation data) from 1982 to 2013.The result showed that the mean green-up dates for Leymus chinensis steppe in Inner Mongolia were mainly occurred between DOY (Day Of Year) 110 and 130,and the green-up dates were advanced at a rate of 2.2 days per decade during 1982-2013.The mean end of season dates for Leymus chinensis steppe in Inner Mongolia were mainly occurred between DOY 255 and 275,which were slightly advanced during 1982-2013.The trend of green-up dates for Leymus chinensis steppe in Inner Mongolia advanced,which was related with the rising spring temperature and the increasing accumulated precipitation between October of the last year and April of this year.The trend of end of season dates also advanced,which was related with the rising temperature of this year,but not related with the precipitation.Therefore,the length of growing season was delayed mainly due to the advanced trend of green-up dates was more obviously than the end of season dates.