To investigate the markedly thermal infrared anomalies in epicentral areas before and after the Qingchuan, Sichuan M_S5.4 earthquake on September 30, 2017 and the Lintan, Gansu M_S4.3 earthquake on October 31, 2017, in this study, we collected TBB data from China's geostationary meteorological satellite FY-2G and analyzed the data and spectra using the wavelet- and relative-power-spectrum transform methods. The results show that the thermal infrared anomaly range of the Qingchuan earthquake is mainly distributed in the southeast of the epicenter, and that power spectrum enhancement occurs about four months prior to the earthquake and lasts for about two months. The thermal infrared anomalies of the Lintan earthquake are mainly distributed southwest of the epicenter, with an anomalous enhancement phenomenon occurring about 20 days prior to the earthquake. With the passage of time, this anomaly range expands further southwest. These anomalies begin to shrink and weaken 14 days before the earthquake, and last for about 30 days. A comparison of the two earthquakes shows that there are many common characteristics in their thermal anomalies, which can provide significant reference information for determining the seismic precursor characteristics of moderate-strong earthquakes.