An ultrasonic-guided wave(UGW) is a very promising tool in the field of structural health monitoring and non-destructive test.Numerical analysis was used to simulate the propagation in the rebar and explore the characteristics of UGW in the steel rebar waveguide.Two-dimensional fast Fourier transform was used to process the numerical results and to evaluate the damage.Subsequently,different UGW test influence factors were investigated.The results clearly showed that both the group velocity and the amplitude of longitudinal modes were not very sensitive to stress and temperature variations.However,the received UGW signal energy decreased with the increasing concrete strength.Finally,the interface condition between the concrete and the rebar was investigated.Time-domain and frequency-domain analyses were used to process the received signals.Different interface delamination lengths of the UGW energy attenuation were analyzed and a relationship was obtained.This study successfully proved that UGW is an effective tool in the non-destructive test of reinforced concrete interface delamination. An ultrasonic-guided wave (UGW) is a very promising tool in the field of structural health monitoring and non-destructive test. Numerical analysis was used to simulate the propagation in the rebar and explore the characteristics of UGW in the steel rebar waveguide. Two -dimensional fast Fourier transform was used to process the numerical results and to evaluate the damage.Subsequently, different UGW test influence factors were investigated. The results clearly showed that both both group velocity and the amplitude of longitudinal modes were not very sensitive to stress and temperature variations.However, the received UGW signal energy decreased with the increasing concrete strength .Finally, the interface condition between the concrete and the rebar was investigated.Time-domain and frequency-domain analyses were used to process the received signals.Different interface delamination lengths of the UGW energy attenuation were analyzed and a relationship was obtained hat UGW is an effective tool in the non-destructive test of reinforced concrete interface delamination.