This paper deals with the premonitory anomalies of some kinematical and dynamical characteristics of seismic waves,i.e.the seismic velocity anomalies and the anomalies of the amplitude ratio of s and p waves before the Tangshan (唐山) strong earthquake (M=7.8) on July 28,1976.By means of three different methods the temporal and spatial variations of the mean seismic vilocity ratio v_p/v_s,the curvature coefficient of the Wadati diagram β and the mean longitudinal wave velocity v_p in this region since 1970 have been researched respectively.At the same time the premonitory anomalous variations of the amplitude relation of the vertical maximum displacements of s and p waves recorded by two groups of seismograph stations have been investigated.
The results obtained form the preliminary study show that:(1) The anomalous variations of the v_p/v_s,β,v_p and As/Ap in this area were very remakable before the Tangshan (唐山)strong earthquake (M=7.8);(2) the characteristics of the v_p/v_s,β and v_p anomalies are similay to those of the corresponding anomalies before some other strong earthquakes in China;(3) the A_p/A_s anomaly corresponds with the velocity anomaly in the general tendency,but its concrete characteristics depends on the directions of the groups of seismograph stations.
Finally,the results obtained in this paper are compared with some other results published about the precursors of Tangshan (唐山) earth quake and a brief discussion has been made also.