NOAA/AVHRR thermal images indicated the presence of positive thermal anomalies that are associated with the large linear structures and fault systems of the Earth's crust. The relation between thermal anomalies and seismic activity was established for Middle Asia on the basis of a 7-year series of thermal images. Thermal anomaly has been located near Beijing, on the border between the mountains and plain. The size of this anomaly is about 700 km long and 50 km wide. The anomaly appeared about 6-24 days before and continued about a week after an earthquake. The anomaly was sensitive to crust earthquakes with a magnitude more than 4.7 and for a distance of up to 500 km. The amplitude of this anomaly was about 3 C.