Abstarct: Leaving behind a multi-millennial history, stepped spillways which consist of a series of steps from near the crest to the upstream toe, are generally used in reservoir dams in order to release floods securely. Due to their extraordinary ability on energy dissipation of the flow, using stepped spillways is now wide spread around the world. Current study was aimed to investigate excrementally the energy loss on edged and non-edged stepped spillways in Nappe flow regime. The research has carried out on a 10 step spillway sample with an angle of 45°. Designed edges were embedded in certain first and mid steps, and the rate of energy loss was calculated per different discharge. The research findings has been showed that in both cases, edged and non-edged steps, the relative energy loss reduced with the increasing discharge, also energy loss was more in the case of edged steps than the non-edged ones. In the case of installing edges separately in the first and mid step, an edge with 1cm height and in the case of simultaneous installation, the edge with 1cm height were introduced as the proper ones. When the step’s first edge was fixed and the mid one was changing, the energy loss was also greater with increasing of edge height in the middle of step. Using water depth before hydraulic jump ( in the case of bubbled flow ) has led to greater estimate on relative energy loss, as well. In addition, locating edges on the spillway’s initial steps decreased the stilling basin length. Research findings also showed that the effect of the sample scale on energy loss estimation was negligible. For the proper place to install the edges, results revealed that in all cases using a higher edge was more appropriate. In the cases that two similar edges located in the first and mid steps, locating edge in first step for an edge with 1 and 5 cm height was more proper; but for a 3 cm high edge, the case was different.