Conversed spillway may be some-times considered the best shape from the applicable point of view according to the dam site. The main function of spillway is energy dissipation. So studying the effect of the spillway conversion on the energy dissipation is very important, In this study the downstream width and the angle of conversion were tested experimentally. The dimensional analysis was used to correlate the different parameters affecting the studied phenomena. Beside that the one dimension momentum equation was used to derive theoretical equation for the tail water depth. The main conclusions are: 1- The conversion decreased energy dissipation and increased downstream water depth and jump length. 2- As the contraction ratio increased, the tail water depth and the jump length decreased and the relative energy loss increased. 3- The conversion angle of (θ\2=2.00O) and (θ\2=2.56O) produced the smallest relative flow depth and jump length, and the largest relative energy loss 4- The theoretical results of energy dissipation were in a good agreement with relative error (± 5%) with the experimental results, so the derived equations can be recommended in the field of applications.