Abstract:Abstract: In order to solve the problem of mountain river to river morphology with the changes of uncertainly sediment supply conditions

based on J. G. Venditti series of flume experiments in sediment supply

coinciding fully the characteristics of bed load sediment movement

a parameter Sp was introduced to describe the intensity of a riverbed form. Study on effects of incoming sediment change on river bed-form

bed load transport and sediment gradation. Results showed that

adding sand to the river bed of the river will affect the bed morphology

bed-load transport rate and channel grading in an armor layer. Sediment supply will caused river bottom again appeared rushed silt changes

eventually variable increase the slope

variable serious the scour and eventually reduce the intensity of the river bed structure Sp; Sediment supply will increase the bed-load transport rate

and sediment supply grain diameter sand for 3 mm of sediment for travelling bed load

and in the value grain diameter for 8 mm of sediment for structure bed load; Sediment supply will refinement river

which grain diameter smaller effect than grain diameter larger of particles effect obviously.After joining the median particle size of 3mm sand over mass median particle size decreases and then increases and median particle size of coarse 8mm insteadly.