Abstract: The over winter amount, pupation and emergence progress,adult population dynamics of Meadow Moth （Loxostege stietiealis L.）were observed systematically in Erdos and Ulan Qab from 2008 to 2009.The results showed that in part of banners/ counties of Erdos and UlanQab in 2008,the over wintering larvae of Loxostege sticticalis distributed widely,and the cocoon amount was higher, in which the over winter cocoon density up to 240/m^2 in Hangjin Banner. In 2009,the average density of over winter cocoon was 86.8/m^2 in Shangdu County （living cocoon density 46.8/m^2）, which was 7.2 times than it in past years. Based on the over winter amount, spring rainfall and honey crops, it could be inferred that larvae of Loxostege sticticalis would cause severe damage in 2009,but actually Loxostege sticticalis larvae made light damage, although with larger winter generation adult amount.Therefore, the effect factors of Loxostege sticticalis forecast need further studying.