Based on the Brightness Temperature(BT) of MODIS satellite infrared,by using monthly departure method,anomaly is analyzed．The result shows that before the 2013 Lushan M7.0 earthquake and the 2013 Minxian M6.6 earthquake two months,anomalous increase of the BT appeared in the very large area．Before Lushan and Minxian earthquakes,distribution of anomalous increase whick recurrently appeared in one area,is obviously controlled by blocks,and it is connected with background of movement of blocks.