Through the ages, the pool-and-weir-fishway have been installed in many rivers in Japan. As time advances, fish-ways fail to function adequately because they are deteriorated, broken or changed flow in the downstream.The main purpose of this study is to make clear the problems of fish-ways and to find better resolution methods to solve it. Therefore, we carried out the model experiment by using the open channel where a pool-and-weir-fish way had been set up.As a result, a promising method to cope with the local scouring and circulation flow at the downstream of fish-way is studied by the model experiment.