Abstract: Boundary layer is separated due to the barrier along the flow border line, thus the circulating flow is strengthened and the flow pattern is deteriorated.It is a common phenomenon in the project of water conservancy, searoute and power station.From the theory of boundary layer control, the size of circulating region in the dwvrr strewn of the barrier can be reduced by using the method of "sucking-spouting" water, which sucks part of the discharge in the upstream of the convex barrier and spouts it in the downstremn of it.The results of tests in the 50 cm width flume show that the method of "sucking-spouting", water is very effectme.