Under the background of rising gas radon concentration in Jiayuguan for many years, an unprecedented change occurred in 2017. However, no earthquake matching the amplitude and duration of the anomaly has occurred in the Qilian Mountains seismic belt. On May 22, 2021, an M_S7.4 earthquake occurred in Maduo, which is 570 km away from the radon measuring point in Jiayuguan. An in-depth analysis of the anomaly reliability, anomaly characteristics before the earthquake, anomaly change after the earthquake, and geological structure background was conducted in this study to determine the relationship between the radon concentration anomaly of gas in the Jiayuguan and Maduo earthquakes. Results show that the anomalous characteristics of the gas radon concentration in Jiayuguan are related to the structure where the earthquake occurred. The anomaly of gas radon concentration shows an annual distortion of 1 year or 6 months for earthquakes that occur along the Qilian Mountains seismic zone. By contrast, the anomaly demonstrates a long-term change in the propensity for earthquakes that occur far away from the Qilian Mountains seismic zone. The decreasing rate of radon concentration in Jiayuguan slowed down and then turned to a recovery state after the Maduo earthquake. The measuring points for gas radon concentration in the Jiayuguan and Maduo earthquakes are both located in the northeastern part of the Tibetan Plateau with the same dynamic background and structural correlation. The comprehensive analysis shows that the tendency anomaly of gas radon in Jiayuguan may be related to the Maduo M_S7.4 earthquake. This study is of considerable importance in establishing a reliable anomaly index system and improving earthquake prediction.