The utility model relates to a but has (b) wall bushing of fire -retardant crowning piezoelectricity cabinet of thermoplasticity (b) of excellent mechanical properties, processing property, electric insulation performance recycling. The wall bushing wholly is flat tubulose shape, and including lumen and pipe wall, the cross -section of lumen is the elliptic type of runway appearance. The wall bushing includes still that the copper bar fixes square hole, shirt rim and wall bushing stiff end. This wall bushing adopts glass fiber reinforcement and the fire -retardant direct injection moulding of the modified material of thermoplastic resin.