为了更好的将地电数据应用于地震前兆分析，研究由于线路故障、直流供电等干扰因素引起的地电场数据变化，尝试使用带阻滤波、经验模态分解等方法排除干扰。处理结果表明，上述方法可以减少干扰因素的影响，有利于有效地提取地震前兆信号。此外，初步分析汶川地震周围台站的HHT（Hilbert-Huang Transform，简称HHT）时频谱变化，研究发现，在距离震中低纬度的小庙、沪沽2个台站在地震发生当天同时出现HHT谱值增加的现象。

In order to distinguish seismic precursory information, this paper studies three interfernce types of the geoelectric field variation affected by line fault、power supply etc. We eliminate interference with the method of empirical mode decomposition、bandstop filter etc. The result shows，useful information can be provided for seismic precursory information and better effect can be obtained. We analysis HHT time-frequency spectrum observed by the stations around the epicenter of Wenchuan after the interference factors have be removed. The result shows that the increased power spectrum were recorded at Xiaomiao and Hudu station on May 12, 2008.