This　paper　proposes　a　comprehensive　evaluation　index　based　on　the　combination　of　acoustic　emission　(AE)　technology　and　principal　component　analysis　(PCA)　to　address　the　issue　of　low　accuracy　of　any　single　AE　parameter　in　identifying　damage　to　wooden　beams　caused　by　accumulative　damage.　Four-point　bending　tests　were　conducted　on　wooden　beams　to　monitor　the　process　of　performance　degradation　and　evaluate　damage　progress.　The　results　indicate　that　the　proposed　comprehensive　evaluation　index　can　divide　the　damage　evolution　process　of　wooden　beams　into　four　stages:　initial　compaction,　elastic　deformation,　crack　propagation,　and　instability　fracture.　These　stages　are　consistent　with　the　mechanical　properties　of　wooden　beams.　The　time　of　crack　initiation　can　also　be　determined　according　to　the　comprehensive　evaluation　index　value.　The　proposed　wooden　beam　damage　detection　method　based　on　the　AE　technique　provides　a　reference　for　further　research　on　the　damage　evolution　mechanism　of　wooden　structures　and　in　situ　monitoring　methods.