Abstract: Calculation methods of conjugate depth and hydraulic jump length of the roughened stilling basin with uniform gravel bed are proposed in this study. According to the test data given by Hughes on the conjugate depth and hydraulic jump length of the roughened stilling basin with the gravel bed， hydraulic jump equation and the change law of hudraulic jump length with the upstream Froude number， upstream supercritical flow depth， downstream subcritical flow depth and roughness height are analized through the dimension concordant principle. The conjugate depth is increasing with the increasing in Froude number and decreasing with increasing in the roughness height. The hydraulic jump length is also the function of the upstream Froude number， upstream supercritical flow depth， downstream subcritical flow depth and roughness height. Meanwhile， energy dissipation ratio in the hydraulic jump region is increasing with increasing in the roughness height. Calculation formulas of the conjugate depth and the hydraulic jump length of the roughened stilling basin with uniform gravel bed, verified by the test results of FGCarollo, are put forward.