Abstract:Abstract According to the studies on exposure degree and equivalent size of our predecessors

start-up and sediment transport rate formula of the right in the upper reaches of the Yangtze River typical was choose. parameters A of coarse degree on typical of the river bed was further defined. Through analysis we could see that the coarse degree in time and space there are changes in laws. Coarse degree was lighter in flood season than in dry season

and it was lighter upstream than downstream. It was not changed with the grain size. The riverbed roughness was a linear trend with coarse degree. According to the limited information

the relation between coarse degreea and riverbed roughness was drawn .