Structural damage of H-shape steel will affect propagation of ultrasonic guided waves. Hence, non-destructive testing technology based on ultrasonic guided waves can realize structural health monitoring (SHM). The possibility of damage size identification of H-shape steel using guided wave approach is discussed. A period sine wave with the center frequency of 87.5 kHz modulated by Hanning window as excitation waveform, the finite element simulation is carried out with commercial finite element analysis software ABAQUS. The finite element modal is then validated by experiment. In experiments, piezoelectric lead zirconate tianate(PZT) wafers are employed to generate excitation waveform propagating in the structures and to collect wave signals as sensors. Taking advantages of morlet wavelet method for the simulation and experiment to process signals collected, the results of experimental measurements and numerical simulation are compared. Finally, the damage depth and thickness influence on damage identification, and the damage identification capability of guided wave in the H-shape steel is analyzed.