Climate change has been an accurate and sensitive indicator of global change in recent years. In order to take the further study on the effects of regional climate change on the plants phenological phase in the desert steppe, monitor the changes of grassland ecological environment, make for crop varieties classification of ecology, natural division of agricultural climate zoning or index, guide the local agriculture and husbandry production, provide the basic theory of strong support, the phenological observation data (the germination date, flowering date, wilting date and growing season length) and corresponding meteorological data from two meteorological stations of the desert steppe in western Inner Mongolia during 1983 to 2009 were used to reveal statistical relationships between phenology and meteorology. The results showed as follows:(1) It showed the ascending trend of annual mean temperature in the desert steppe in Inner Mongolia, the increased rate was about 0.34~0.75℃/10a and the change of precipitation was not apparent. The climate was getting warmer and drier. (2) Most plants′green up dates was intensely affected by mean tempreture and precipitation in spring (from March to May), the dates were 0.1~0.6 d/a in advance except Puccinellia distans L. The flowering periods of the dominant species were also becoming earlier. For instance, flowering dates of Sarcozygium xanthoxylum Bunge and Oxytropis aciphylla Ledeb. in Xilingaole was getting ahead at 0.5 d/a and 1.1 d/a degrees respectively. The wilting date was influenced by the water and heat condition from late summer to early autumn and they were different at two stations. Species withered in Wushenzhao postponed for about 0.6~0.8 d/a while plants turned yellow in Xilingaole had an exhibition of the trend of the advance because the date of withered stage was closely related to precipitation and tempreture prior to withering and yellowing in Xilingaole. (3)With the climate warming, the growing season lengths of all the tested species had prolonged though their phenological phases had changed.% 近年来,植物物候已成为全球变化敏感而准确的综合指示器.深入研究区域气候变化对草原优势牧草生长发育的影响和监测草原生态环境变化,对指导当地农牧业生产、作物品种的生态学分类、自然区划或农业气候区划的指标,提供有力的基础理论支持.文章基于内蒙古西部荒漠化草原乌审召和锡林高勒两个牧业气象试验站1983—2009年优势牧草的物候期数据和同期气象数据,在分析年平均气温、年降水量和牧草物候期各指标线性趋势的基础上,研究了气候变化对内蒙古荒漠化草原优势牧草返青、开花与黄枯日期早晚的影响,结果表明：(1)1983—2007年内蒙古荒漠化草原区年平均气温升高明显,气候倾向率在0.34~0.57℃/10a 之间,年降水量无显著变化,气候朝着暖干化方向发展.(2)受春季气温和降水的影响,27年间内蒙古荒漠化草原区供试草种中,除乌审召的碱茅返青呈现明显的延后趋势,平均每年延后0.6 d外,大部分牧草发育期呈提早趋势,幅度为0.1~0.6 d/a；研究期间,优势牧草的开花期总体呈提早趋势,其中锡林高勒的霸王和猫头刺开花提早最为显著,二者始花日期平均每年提前0.5 d和1.1 d；在夏末初秋气温和降水的综合影响下,内蒙古荒漠化草原区不同站点优势牧草的黄枯期变化差异明显,其中乌审召的优势牧草黄枯均表现为显著或极显著的延后趋势,幅度为0.6 d~0.8 d/a；而锡林高勒优势牧草的黄枯期则大部分表现为不显著的提前态势,究其原因,是由于锡林高勒站点在牧草黄枯前1~2个月气温升高和降水量减少所致.(3)虽然荒漠化草原区各草种物候期均有所变化,但整体上在气候变暖的背景下,所有供试植物生长季均不同程度的延长.
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