Based on inspecting and investigating the situations of biological hazard of ancient architecture such as north-south building,Fuyi temple and Yuquanguan,species of diseases and its hazard scope and hazard degree were recorded.The results showed that timber structures had some problems such as coloured drawing of purlin post,Fang,bucket arches had fell off;rot,infesting,colour spot,sediments on the surface,rupture,warp,breading plant etc.