Abstract: A supplementary energy dissipater of suspension beam arrays in a low head stilling basin is examined in this study using an experiment of 40 orthogonal tests and a bundling method, focusing on its hydrodynamic characteristics under different beam arrangements including a new arrangement featured with a variable beam spacing and inclined beam installation between the upper and lower arrays. The results show that variation in beam spacing reduces water head or increases energy dissipation rate effectively, thereby leading to an increase of 12.15% in the in-basin water head variation relative to that of fixed spacing. And the inclined beam schemes generally help reduce water head in the cases of fixed and variable spacing, but forward inclination is better allowing the in-basin water head variation of possibly 48.76% and 10.71% larger in the two cases respectively. From the experiment, we obtained the optimal designs ? forward inclined beams of spacing 8, 8, 8, 12, 12 and 4 cm in six bundled tests respectively.