Abstract: This paper introduces the research of the relationship between the data abnormality of atmospheric electric field near the ground surface and the earthquake in Sichuan province. Throughout the analysis of abnormal data of two atmospheric electric field mill which located 50 kilometers away from the epicenter a month before the Wenchuan earthquake happens, this paper find that the abnormal electric field near ground surface last more than 8 hours before earthquake happens. Also, the variation regularity of the surface electric field waveform and peak value is different from that caused by lightning and other weather phenomena. Above all, by analyzing the abnormal electric field data before earthquake, this paper can achieve a new method to monitor and forecast the earthquake.