This study presents an experimental investigation of wood damaged by deflection from structural characteristics of hip rafter protrusions in traditional wooden frames. First, after the reinforcing damaged wood with a carbon fiber bar, the hip rafter was restrengthened by steel plates. Structural behaviors and reinforcement effects were examined through the experiment of the hip rafter. As a result of the hip rafter experiment, it was found that the specimen of damaged wood restrengthened by steel plates showed the reinforcement effects including an increase of yield load, ultimate load, and initial and plastic region stiffness, and internal lift control. In the comparison between theoretical and experimental values of ultimate load, experimental values were mostly higher than theoretical values. In addition, experimental values of the reinforced specimen were 9~70% higher than its theoretical values compared to the standard specimen and as the protruded length rate increased, reinforcement effects were remarkable. Restrengthening of the steel plate with bolt and nail in the reinforced specimen increased structural reinforcement effects with 6.4~9.2% in yield load and 9.3~12.6% in ultimate load compared to reinforcement with bolt only. Finally, it is considered that as reinforcement with steel plates can control external deflection and internal lift of hip rafter, structural reinforcement with steel plates, bolt and nail on the characteristics of natural wood material will be desirable.