Abstract: By using th e observed data related to grass growth and meteorological conditions during ten continual growing seasons from 2005 to 2014 in Arhorchin Banner, the relationship between hay yield of natural and meteorological conditions were comprehensively studied and analyzed. The results showed that the annual precipitation significantly correlated with hay yield with the simple correlation coeffocients was 0.775,the direct path coefficients was 0.788 in Arhorchin Banner, whereas the annual average temperaturedid not significantly correlated with hay yield, which implied annual precipitation was the most important factor in determining hay yield. Therefore, the main meteorological factors to influence the forage growth and yield in this area were short of precipitation.