Ying-hua　Palace　in　the　Forbidden　City　is　taken　as　an　example.　FEM　of　Chinese　ancient　wood　structure　is　built　on　the　basement　of　hypothesizes　that　tenon-mortise　joints　are　considered　as　semi-rigid　elements　and　tou-kungs　are　considered　as　3-dimensional　springs.　By　modal　analysis　the　first　10　periods　as　well　as　vibration　modes　are　obtained.　Then　Tianjin　seismic　waves　in　3　dimensions　are　input　and　response　curves　of　typical　nodes　as　well　as　elements　are　studied.　Aseismic　characters　of　constitutions　such　as　tenon-mortise　joints,　tou-kung　and　ce-jiao　are　discussed.　Results　indicate　that　base　frequency　of　Ying-hua　Palace　is　low,　whose　main　mode　in　x　direction　forcuses　on　No　1　and　No　2　on　y　direction;　Under　seismic　forces　responses　of　roof　are　weaker　that　those　of　top　of　columns;　Constitutions　of　tenon-mortise　joints,　tou-kung　and　ce-jiao　are　helpful　for　seismic　resistance　of　ancient　structure.