Abstract: The front edge of T300 carbon fiber reinforced resin based composite wainscot fractured during service.The fracture mode and fracture course of the front edge of the composite wainscot were analyzed by inspecting the appearance and fracture surface.Static experiments,finite element analysis and nondestructive examination were also carried out and the fracture reason of the composite wainscot was concluded.The results show that the junction of wainscot air flow surface and beam was the weak region,and when received force the defects between main layer group and bend layer group made it cracked first,then delaminated,and finally fractured.It is suggested that whether the process can satisfy the demand of structure integrity and accidental external loads should be paid more attention in design of the structure of the composite materials.