徐庄子台GM4磁力仪自2007年6月观测以来，一直受同台电阻率直流供电的干扰，在干扰时段内，GM4分钟值数据不能真实的反应磁场的变化，这样给数据的处理和分析都带来了很大的困难，不能很好的服务于地震监测预报。本文探讨了地电直流供电对GM4分钟值数据干扰的解决方案，并介绍了按解决方案进行施工改造的效果。结果表明，引入地埋铠装电缆布设外线，可以屏蔽掉直流供电所产生的一部分感应磁场，较好的解决台站场地条件的限制，提高了GM4分钟值数据的观测质量。

 The GM4 magnetometer of Xuzhuangzi Observatory has been disturbed by the meanwhile observation of geoelectricity resistivity since it was carried out on June 2007,it brings a great difficulty in data processing and analysis,as the data can’t reflect the actual varities of the geomagnetic field at the interference period,also degrades the value of earthquake monitoring and prediction.This paper give a solution on how to avoid the DC interference which is resourced from the observation of geoelectricity resistivity.In fact,it is the reformation of the geoelectricity outside cable constructional style that shield much more magnetic field induced by DC power supply,and improve the GM4 data quality finally. 

Key words: Resistivity; GM4; DC interference; scheme; effect; quality