Weirs are widely used as discharge measuring device in laboratories, industries and irrigation channels, studied combined orifice-weir flow is a complex phenomenon in hydropower and the discharge capacity of a structure which affects the safety of the structure. In this paper, an experimental study investigate total energy loss through combined weir with different relative width, relative height and gate opening with different relative diameter to improve characteristics of hydraulic jump and reduction scour from weirs. The result showed that, maximum relative energy loss at relative combined weir width = 0.13 but the relative minimum = 0.23, maximum relative energy loss at relative combined weir height =0.18 but the relative minimum =0.12 and maximum relative energy loss at the relative diameter of gate opening in combined weir = 0.2 but the relative minimum = 0.4 . Measured and predicted data were agree well and gave standard error = 0.012, correlation coefficient = 97%. Predicted equation (4) for relative energy loss using multiple linear regressions data agree well with the measured data Boundary condition for (Initial Froude number = 1.3 to 1.5, relative width of combined weir = 0.13 to 0.23, relative height of combined weir = 0.12 to 0.22 and relative diameter of gate opening in combined weir = 0.2 to 0.4 ).