Big　scale　shaking　table　model　tests　are　performed　on　tunnel　portal　parts,　in　order　to　learn　about　the　effect　of　shock　absorption　layer　on　the　dynamic　response　of　lining　and　front　slope　during　earthquakes.　In　this　modeling　test,　two　cases　with　and　without　shock　absorption　layer　respectively,　are　executed　to　analyze　the　behaviors　of　shock　absorption　layer.　The　analysis　results　show　that:　the　shock　absorption　layer　can　weaken　the　amplified　effect　of　acceleration　and　displacements　of　tunnel　structures　exist　at　the　area　which　is　of　some　distance　from　the　entrance　of　the　tunnel,　and　reduce　the　vibration　of　lining　transmitting　from　the　surrounding　rock.　The　strains　of　lining　are　reduced　during　the　earthquake　because　of　the　shock　absorption　layer,　especially　on　arch　waist　and　arch　feet,　which　could　be　seen　as　strain　concentration　zone,　and　the　shock　absorption　layer　can　make　strain　of　lining　uniformity.　As　the　increasing　of　the　PGA　of　input　seismic　wave.　there　is　no　invalidation,　but　will　be　improved　on　damping　efficiency.　Whether　or　not　the　shock　absorption　layer　is　installed,　there　is　not　much　differences　on　the　acceleration　response　of　surrounding　rock,　and　the　amplified　effect　along　the　slope　surface　is　still　obvious,　which　make　the　slump　on　the　slope　easier　to　occur,　especially　on　the　top　of　the　slope.　But　there　is　the　surface　failure,　and　we　should　focus　on　that　the　tunnel　openings　are　usually　partially　or　completely　buried,　which　severely　affect　the　normal　use　of　tunnel.