Abstract: Taking the ATG-6138M vapormeter of Huailai No.4 Well in Houhaoyao seismic station as the research object, we analyzed and excluded the interference factors of its observation, and provided a reference for correctly identifying the pre-earthquake anomaly information. The observation quality of ATG-6138M vapormeter and the DFG-B vapormeter are contrastively analyzed using origin data statistical software. The result shows that: data changes of the ATG-6138M vapormeter are more sensitive and its observation quality is better than that of the DFG-B vapormeter. At the same time, it is found that the concentration of gas mercury in Huailai No.4Well is mainly affected by the temperature of observation room and dynamic level in well.