River optimization requires a profound understanding of flow pattern from morphodynamic point of view. Vegetation on banks of natural channels exercises a significant influence on the flow structure. In open channel hydraulics, vegetation often causes changes in the flow resistance, usually resulting in the increase of flood stage. The interaction between vegetation and the flow structure impacts sediment and contaminant traort, resistance to flow, fluvial geomorphology, and riparian life. Understanding the impact of vegetation on flow is therefore important in river restoration, and determining the retardation in channels is important in design of restoration works.There exists no information for decelerating flow with small aspect ratio in open channels and vegetation on banks, even though flow in many sections of rivers including in pools in coarse-bed rivers is decelerating. Therefore, the objectives of this study are: 1- to experimentally study the effect of vegetation on banks on flow in gravel-bed channels; 2- to assess the validity of the log law and the Coles law for decelerating flow when vegetation is present on banks; 3- to observe the Reynolds stress distribution under decelerating flow when vegetation is present on banks; and 4- to compare the results with the case of flow in gravel-bed channels without vegetation on banks. Experiments were carried out in an 7-m-long, 32-cm-wide, and 35-cm-high recirculating flume at the Hydraulics Laboratory of Isfahan University of Technology. The flume had glass banks and glass bottom on which gravel particles were deposited. The gravel particles used had a median diameter (d50) of 33.7 mm. the bottom slope was obtained by varying the thickness of the gravel layer along the flume to obtain the slope of +2%. An Acoustic Doppler Velocimetry was used to measure parameters of turbulent flow. Experiments carried out in five series:1- Gravel bottom, bare bank and uniform flow. 2- Gravel bottom, bare bank and decelerating flow. 3- Gravel bottom, rice stems on banks and decelerating flow. 4- Gravel bottom, straw stems on banks and decelerating flow. 5- Gravel bottom, typha stems on banks and decelerating flow. The whole stems situated inside the water were fixed on the banks.The measurement reach was situated between 5.5 x(m) 6.5, where x was measured from the flume entrance. Within this measurement reach, the flow was considered to be fully developed. To investigate the influence of bank vegetation cover on velocity and the Reynolds stress at each section, flow velocities were measured at different distances from the bank (D=0.03, 0.05,n, showing no and 0.15 m) .The results showed that in the presence of vegetation in the velocity distribution took on a convaxe shape and velocity distribution is different from bare bank channels. Validation of log law makes possible to estimate shear velocity and obtain a better estimation from resistance to flow in gravel-bed channels with the vegetated banks. and maximum velocity occurs under the water surface. Vegetated banks alters the velocity, Rynolds Sress and RMS distributions, showing non-linear shap with maximom value under the water surfer. Keywords: : Decelerating flow, Vegetated banks, Gravel beds, Aspect ratio, Rynolds Stress.