Based on meteorological data from Xilinhot National Climate Observing Station in 1954 to 2015 and monthly observational data of Cleistogenes squarrosa in 1986~2015, the correlation between the yield, growth stages of C. squarrosa and air temperature and precipitation was determined with correlation analysis method, and the major factors controlling the yield and phenophases of C. squarrosa were found out. The results indicated that:the annual average of temperature in Xilinguole typical grassland in 1986~2015 showed an increasing tendency,and the precipitation showed a downward trend from 1954 to 2015, the climatic tendency of Xilinguole typical grassland is dry-warming. As a result, the length of growing season of C. squarrosa was shortened with returning green date be delayed whilst the heading date, flowering date, mature date, and wilting stage become early to different extent. The major factors limiting grass yield were precipitation in growth season and annual precipitation, the correlation coefficients were 0.458(P<0.05), 0.508(P<0.01); air temperature had no significant effect on grass yield. Precipitation in growing season impacted the growth of C. squarrosa significantly.