Taking the flood damage of a barrage in Baihe River as an example, this paper discusses the role of hydraulic model technology in the post-disaster reconstruction scheme of water conservancy projects. In the hydraulic model test of the original scheme, it was found that the flow pattern, flow velocity distribution, energy dissipation rate and downstream river erosion all did not meet the expectations. In view of the adverse phenomena found, we proposed to change the shape of the pier head and pier tail of the inlet gate chamber to the streamline type, and add stilling buckets to different parts of the downstream apron of the stilling basin, so as to provide reference for the post-disaster reconstruction scheme. In the test, the hydraulic model test technology can accurately find the unfavorable factors and potential problems in the original design scheme, and can put forward specific suggestions for modification, so as to save time and cost and speed up the pace of post-disaster reconstruction.