Based on all geoelectric and geomagnetic data observed in 6 years at Sino-France cooperate station,in contrasting of annual variation for years, the observation data in measuring lines are selected reasonably and the time series curves are plotted by these data. It is discovered that normal background fluctuation is added the variation of distortion for a month and more before western Kun Lun Mountain earthquake M_S=8.1. According to the distortional shape, there are 2 kinds of forms:the step abrupt change and the sudden change with single needle shape. A possible mechanism of 2 kinds anomaly is discussed in this paper.