Abstract: In order to provide scientific basis for rational utilizing of grassland,improving forage yield in per unit area and addressing climate change,the key meteorological factors influencing the community characteristics of Leymus Chinensis in Evenk Autonomous County meadow steppe,the northeast part of Inner Mongolia, were revealed by correlation analysis between the changing law of growth and development of Leymus Chinensis community and meteorological factors.The results showed that heading date and grain mature date could be influenced by a number of factors.Other meteorological factors were found to have great impact on growth and development of Leymus Chinensis in spite of the positive relationship between the time of heading date and grain maturity date.By the comparative analysis based on mass data,we found that single factors,temperature or precipitation had different influences on the time of Leymus Chinensis developmental phases.Temperature or precipitation showed positive effects on growth and development of Leymus Chinensis in late-April to mid-May.Earlier heading trends of Leymus Chinensis could be observed with high temperatures and high precipitation when other conditions were constant. Temperature or precipitation at the basic level in Late-June to Late-July showed negative effects on growth and development of Leymus Chinensis.High temperatures and precipitation resulted in the later grain maturity.