The characteristics of shear wave splitting before and after the Yongdeng M_S5.8 earthquake on July 22,1995 are studied by using the digital seismic records from 1990 to 1995 of Lanzhou station in CDSN network and the several records of Langsuo station which was established jointly by China and France.The time-delays of splitting shear waves and the polarization directions of fast shear waves are determined quantitatively by using Maximum-Eigenvalue (ME) method,Wave Distinguish Factor (WDF) method and Maximum-Likelihood (ML) method.The results show that the time-delay of splitting shear waves began to increase about one year before the earthquake,the polarization direction of fast shear waves turned from NE to NW-before the event,and that the time-delay of splitting shear waves and the polarization direction of fast shear waves became normal very fast after the earthquake.The variations in the time-delay are similar to the results from Peacock (1988) and the variations in polarization direction of fast shear waves are similar to that before and after the Sunan earthquake (1990).