In design of an open channel,the slope of channel is usually designed by the theory of uniform flow of channel.When the channel is so short that flow in it can not become uniform flow,it must be calculated with the theory of steady gradually varied flow.By now,no paper is found to have discussed this problem.So in this paper,an analysis was given about the relation between flow profile and slope of channel based on the engineering examples,referring to four types of flow profile,and variable searching regio...