Weirs are one of the main heading-up water structures. It is constructed along waterways to control for head, discharge and sometimes load sediment. The sedimentation depth increases upstream a weir due to decreasing velocity in the zone of backwater curve as an example of the High Aswan Dam. A weir used to pass flow above crest level. The main objectives of this research study effect of sedimentation depth and length in upstream of weir on the flow characteristics and efficiency. The research methodology included experimental, theoretical and statically studies. The depth of sedimentation takes 25%, 50%, 75%, and 100% from the weir height and the length of sedimentation take 50%, 100%, 150%, 200% and 250% from weir height. All models tested at different channel bed slopes, 0:0, 1:500, 1:250, 1:200 and 1:150. The main Conclusions are: 1. The discharge coefficient Cd increases as the ratio of H/P increase for no sediment and with sediment at different upstream sediment depth 5cm<he<20cm, and lengths 10cm<Le<50cm at different channel bed slope 0.0<S<0.01. 2. Developed new Discharge Stage relationship for case of sediment and no sediment to Fayoum weir and fined the correction factor between two cases. 3. The upstream suspended sediment of Fayoum weir decrease from upstream head losses when compared with no sediment. 4. The increases of volume of sediment causes from flow characteristics for 0.0<Vs/VT<1.00. 5. The increase in bed channel slope cause increase in length of hydraulic jump length with sediment in upstream of Fayoum weir when compared with no sediment. 6. Developed different statistical empirical formula to compute discharge coefficient of Fayoum weir in cases of sediment and no sediment in upstream depend on different flow parameter as upstream head, height of weir, length of weir crest, channel bed slope, and volume of upstream sediment. 7. The verification of developed formula give good results when compared with other experimental data. 8. The main conclusion from the present research that the sediment in upstream Fayoum weir have positive reaction on the flow characteristic.