After processing the data of geoelectric field and geomagnetic component from Tianzhu sino-France coorperate station in Oct. 1994 to Jun. 1997, with methods of mean value analysis, fractional dimension, vertical polarization direction projection and two-dimension inversion of fixed-set MT, it is found out that the 5 parameters in the 4 methods take on short-impending anormalies in different extent before Yongdeng M_S 5.8 earthquake (Δ=84 km)on July 22, 1995 and Tianzhu M_S 5.4 earthquake (Δ=65 km)on June 1, 1996. All these anormalies show good coordination, and the fractional dimension and principal-axis apparent resistivity anormalies show clear orientation. The anormalies of geoelectric field is more sensitive to the earthquake preparation process of Tianzhou event which took place on the same fault with the station. The anormaly reliability is discussed from 4 points and the anormaly possible mechanism is given. It is suggested that the geoelectric anormaly before Yongdeng M_S5.8 earthquake is produced mainly by the focus electromagnetic radiation, comline with electric property variation of medium under the station at depth of 7 km, while before Tianzhu M_S5.4 earthquake mainly by the resistivity variation of rock along the fault strike at depth of 5~30 km under the station.