The embodiment of the invention provides a riverway engineering quality detection method, which comprises the steps of determining a survey line interval based on a multi-beam measurement principle, determining whether round-trip measurement and ship speed measurement are needed or not, and obtaining topographic data required by engineering quality detection; adding correction points in terrain data preprocessing, so that the positions of any two stages of engineering terrain grid planes generated by the ARCGIS are in one-to-one correspondence; selecting a corresponding grid interpolation algorithm according to different projects, and subtracting two stages of terrain grids; extracting a subtraction value, namely an elevation change value, and respectively extracting two stages of gradient values; forming original data, elevation change values and slope value table files which are in one-to-one correspondence, and calculating to obtain parameter values required by engineering qualitydetection; and determining the river engineering quality according to engineering standard requirements. A digital model for determining the multi-beam underwater topography measurement method is provided, and the multi-beam measurement technology is more standard; defects existing in section comparison detection are overcome, terrain characteristics are considered to achieve two-stage terrain full-coverage comparison, and data processing is more scientific and efficient.