On the basis of daily ground temperature observation, the analysis of characteristics of abnormal data, data processing methods, and the influences of improper maintenance of the ground temperature observations field on data quality are analyzed. The results show that the increased and unstable discrepancies between the data from automatic weather station and manual observation are caused by the abnormal sensor performance. The treatment of the abnormal data in the monthly report database should be conducted according to the actual situation. The differences of soil heterogeneous properties in groundtemperature observation field, the placement of thermometers, and the changes of the surrounding environment all can bring about the errors of the qualitycontrolled data, which needs close attention of weather observers.