The evolution characteristic of long-straight section channel often appears the unsteadiness of the beaches and the thalweg in the changeover portion,which causes the change of navigation channel.Taking a typical long-straight section channel named Mayangtan in the downstream of the Hanjiang River as an example,and based on the analysis of river evolution,model test and regulation effect before and after the regulation project,we summarize the experience of the long-straight section channel regulation project in the downstream of the Hanjiang River.The results show that,for the unsteadiness of the beaches and the thalweg in the long-straight channel,we shall plan reasonably the channel axis and take engineering measures to create micro-bend regulation lines,so as to stabilize effectively the navigation channel.When a lower regulation water level is adopted,by narrowing the width of regulation lines and the distance between regulating structures,the purpose of improving the channel scale of the transition section can be achieved.