Abstract:This paper,describes the seismic velocity ratio anomaly of the Tuolai Ms 6.0 earthquake on October 26,1993,in middle-west section of Qilian Mountain.Hexi area,and discusses the medium-short prediction inedx. Based on the studies of Tuolai earthquake,it is considered that the region where the edge of the area concentrating lower value points of seismic velocity ratio intersects the seismic belt with lower velocity ratio anomaly value would be the location of future earthquake.Successively lower value anomaly of the seismic velocity ratio after several moderate earthquakes and obvious re-rising of velocity ratio value between 1 and 6 months before a stronger earthquake are taken as tendency anomaly and a short-term index to predict the stronger earthquake,respectively.