Abstract: On basis of seismic phase data in Anhui province and its surrounding area, a velocity ratio of seismic waves(Vp/Vs) calculating program is write according to the Wadati method for calculating velocity ratio of seismic waves(Vp/Vs), and results of the program to data of large seismic network and data of small seismic network are contrastively analyzed.The analysis shows that the scale of seismic network has little effect on the calculating result.In addition, analysis of the effect of spatial distribution of seismic station shows that, the variation range of wave velocity ratio decrease as wave velocity ratio limit according to station distance added the calculating process, and the anomaly period become more clear, and so, it is necessary to add wave velocity ratio limit according to station distance while calculating wave velocity ratio time series.In this paper, 7 wave velocity ratio time series before moderate-strong earthquakes are calculated and 5 of them show wave velocity ratio anomaly before the earthquakes, further more, earthquake cases summarizing indicates that in Eastern China, it is relatively reasonable to adopt 3°×3°area around the epicenter of a M_S5.5 earthquake and 2°×2° area around the epicenter of an earthquake of about M_s4.5 while calculating wave velocity ratio.