The thermal infrared anomaly characteristics of 14 moderately strong earthquakes happened in the mainland and adjacent sea of China are extracted and analyzed by wavelet transform and relative power spectrum calculation according to the remote sensing brightness temperature data from geostationary meteorological satellites FY-2C/2E of China. The anomaly characteristics include: (1) Anomalies have obvious characteristic periods. The periods for mainland earthquakes are 13 days and 64 days and those for sea earthquakes are less than 32 days. The earthquakes with similar epicentral positions have the same characteristic periods; (2) Maximum anomaly amplitude is obvious and easy to be identified. Most of the amplitude is more than 8 times, and even up to 20 times; (3) Earthquakes are located in the interior and edges of anomaly regions. The transition areas in which anomalies appear and disappear are possible epicenters; (4) Earthquakes happened in arid areas have longer characteristic periods and those happened in wet areas have shorter characteristic periods; (5) The relationship between maximum anomaly occurring time and earthquake happening time and the relationship between anomaly peak and amplitude are not clear yet; (6) By comparison, mainland earthquakes and sea earthquakes have the similarity in above relationships, but their characteristic periods and anomaly areas are different.