Abstract: In view of the limitation of existing corrosion detection methods for reinforced concrete, a nondestructive detection method based on microwave transmission and reflection method proposed. The simulation model of rectangular waveguide scanning reinforced concrete foundation established, and the variation of scattering parameters S₂₁ and S₁₁ corrosion analyzed, and the influence of waveguide working frequency on the detection effect studied. Through carrying out microwave non-destructive experiments of reinforced concrete structures, the effectiveness of the simulation method was verified. The results show that the corrosion detection of reinforced concrete structure can be realized based on S₂₁ and S₁₁ changes in amplitude before and after steel corrosion. The transmission detection method less affected by frequency, while the reflection detection method more affected by frequency the operating frequency of the waveguide should be reasonably selected according to the size of the corrosion site.