The invention provides a detection method of thick beam structure damage based on guide wave, comprising the following steps: arrangement of transducer, arrangement of excitation signal, generation, spread and collection of the excitation signal, and signal processing and analysis, and damage identification. Owing to the reasonable arrangement of an exciter and a sensor and appropriate arrangement of the excitation signal, damage waveform signal of a thick beam object in a project can be collected. Besides, information indicating position and degree of damage can be obtained by waveform extraction and analysis, thus realizing sound monitoring and the damage detection of thick beam.