Tenon-Mortise　joint　is　the　main　connection　mode　between　beam　and　column　of　Chinese　ancient　wood　structures.　The　joint　usually　consists　of　two　types:straight　joint　and　Yan-Wei　joint.　Both　types　are　considered　and　simulation　techniques　are　used　to　find　out　the　characters　of　the　joints＇　displacement,friction　force　and　equivalent　stress　and　so　on　during　the　process　that　tenon　is　pulled　out　of　the　mortise.　Results　indicate　that　while　the　straight　tenon　is　pulled　out　of　mortise,the　displacement　and　stress　of　the　joint　are　very　small　and　so　that　it　is　hard　to　be　destroyed.　On　the　other　hand,　although　the　Yan-Wei　tenon　is　difficult　to　be　pulled,once　it　is　pulled　out　of　the　mortise,it　extrudes　the　mortise　which　will　lead　to　the　destruction　of　the　joint.　The　result　is　helpful　for　protection　of　Chinese　ancient　buildings.