Abstract: Rock-filled embankment has become a general type of road embankment in mountain area. But, there is a lack of the study about its stability in the condition of seismicity.There is a time of seismic vibrancy since Wenchuang earthquake in China. So it is necessary to carry study about highway embankment stability in high seismic region.This paper studies the stability and deformation of high rock-fill embankment which is under the conditions of nature,immersion and seismicity from K112+908.16 to K113+675 along Ya-Lu high way.The findings include the following. Reinforcing the embankment lateral constraints and reducing its lateral deformation are the precondition of a stable embankment and no road tensile openings under traffic loads. In the condition of water immersion,the embankment stability has a little change. But the action of wave scouring should be paid attention.In the condition of VIII degree earthquake intensity,the embankment would be fail by the way of pure aside slide. The slide plane would be the interface between embankment and foundation soil.So it will be effective to improve the ability of resisting seismicity that the strength of interface is enhanced.It is an effective measure to improve the embankment strength and reduce deformation that the degree of compaction is enlarged.But it is not better and better as the degree of compaction becomes bigger.There is a necessary study about the relation between the degree of compaction and bearing capacity of foundation soil.