Abstract: Based on the classification of the geoelectric field, the E_T of geoelectric field of Xingji seismic station is extracted at the time when the space electromagnetic environment is calm and the daily deformation of the geoelectric field is stable. Then, the total E_T of the geoelectric field is synthesized by using the orthogonal two-channel geoelectrical field. The azimuth variation of the total geoelectrical field is analyzed: the azimuth angle is calculated and the scatter plot is drawn. The azimuth of the geoelectric field in Xingji Seismic Station is more discrete than that in Pingliang and Dabaisha. Tha data does not have the characteristics of three-stage steady-state variation. Harmonic fitting was used to analyze the harmonics of the electric field data of Xingji, Pingliang, Dabaishe and Changli stations. The differences of harmonic components of these stations were analyzed by harmonic fitting degree and f-test, furthermore, the reason of the instability of the azimuth data before and after noon in geoelectric field of Xingji sataion is analyzed. The low fitting degree of the first 10 order harmonics and the obvious high order harmonics in Xingji Seismic Station geoelectric field indicate that the complex composition of the field in Xingji Seismic Station may be the cause of the dispersion of the azimuth data of the geoelectric field in a day. Finally, it provides a reference for understanding the composition and extraction of the geoelectric field.